135-564: Commercial Orbital Transportation Services ( COTS ) was a NASA program to spur the development of private spacecraft and launch vehicles for deliveries to the International Space Station (ISS). Launched in 2006, COTS successfully concluded in 2013 after completing all demonstration flights. NASA's final report on the program considered it a success and a model for future public-private collaboration. Compared to traditional cost-plus contracts employed by NASA, such as
270-412: A 2010 NASA study, an additional flight of an Ares V heavy launch vehicle was required to stage a US government Mars reference mission due to 70 tons of boiloff, assuming 0.1% boiloff/day for hydrolox propellant. The study identified the need to decrease the design boiloff rate by an order of magnitude or more. Approaches to the design of low Earth orbit (LEO) propellant depots were also discussed in
405-518: A consortium of participants from NASA, industry and academia, discussed propellant depot concepts and plans on several occasions in 2010, with presentations of optimal depot locations for human space exploration beyond low Earth orbit, a proposed simpler (single vehicle) first-generation propellant depot and six important propellant-depot-related technologies for reusable cislunar transportation. NASA also has plans to mature techniques for enabling and enhancing space flights that use propellant depots in
540-403: A contract to Kistler Aerospace (which later became Rocketplane Kistler) for $ 227 million, despite the fact that Kistler had already filed for bankruptcy a year before. Some observers saw this as a gift for the head of Kistler, NASA legend George Mueller . This upset Elon Musk , as there had not been a competition and Musk could have used the funding at SpaceX . Musk protested, and NASA withdrew
675-524: A cooperative effort by NASA's Ames Research Center , Glenn Research Center , and Marshall Space Flight Center (MSFC) was implemented to develop ZBO concepts for in-space cryogenic storage. The main program element was a large-scale, ZBO demonstration using the MSFC multipurpose hydrogen test bed (MHTB) – 18.10 m3 L H 2 tank (about 1300 kg of H 2 ). A commercial cryocooler was interfaced with an existing MHTB spray bar mixer and insulation system in
810-470: A cryogenic fuel management technique that might be used in future propellant depots. The proposed Simple Depot PTSD mission would use several techniques to achieve adequate settling for propellant transfer. In the absence of gravity, propellant transfer is somewhat more difficult, since liquids can float away from the inlet. As part of the Orbital Express mission in 2007, hydrazine propellant
945-446: A customer, the depot's tanks will need refilling. Organizing the construction and launch of the tanker rockets bearing the new fuel is the responsibility of the propellant depot's operator. Since space agencies like NASA hope to be purchasers rather than owners, possible operators include the aerospace company that constructed the depot, manufacturers of the rockets, a specialist space depot company, or an oil/chemical company that refines
1080-628: A decade of reliance on the Russians. In 2019, NASA announced the Artemis program , intending to return to the Moon and establish a permanent human presence. This was paired with the Artemis Accords with partner nations to establish rules of behavior and norms of space commercialization on the Moon. In 2023, NASA established the Moon to Mars Program office. The office is designed to oversee
1215-580: A depot in Mars orbit has also been suggested. In 2024, on Starship’s third integrated flight , propellant transfer in orbit was demonstrated, a capability required to land a crew on the Moon with the Starship HLS vehicle. For rockets and space vehicles, propellants usually take up 2/3 or more of their total mass. Large upper-stage rocket engines generally use a cryogenic fuel like liquid hydrogen and liquid oxygen (LOX) as an oxidizer because of
1350-522: A depot, the launch vehicle size can be reduced and the flight rate increased. Since the accumulation of propellant may take many weeks to months, careful consideration must be given to boiloff mitigation. In simple terms, a passive cryogenic depot is a transfer stage with stretched propellant tanks, additional insulation, and a sun shield. In one concept, hydrogen boiloff is also redirected to reduce or eliminate liquid oxygen boiloff and then used for attitude control, power, or reboost. An active cryogenic depot
1485-432: A hybrid thermal control system could eliminate boiloff of cryogenic propellants. The hardware consisted of a pressurized 50 cu ft (1,400 litres) tank insulated with 34 layers of insulation , a condenser, and a Gifford-McMahon (GM) cryocooler that has a cooling capacity of 15 to 17.5 watts (W). Liquid hydrogen was the test fluid. The test tank was installed into a vacuum chamber, simulating space vacuum. In 2001,
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#17327753946211620-403: A large portion of a rocket is propellant at time of launch, proponents point out several advantages of using a propellant depot architecture. Spacecraft could be launched unfueled and thus require less structural mass, or the depot tanker itself could serve as the second-stage on launch when it is reusable. An on-orbit market for refueling may be created where competition to deliver propellant for
1755-647: A month after the Soviet Yuri Gagarin became the first human in space, executing a full orbital spaceflight. NASA's first orbital spaceflight was conducted by John Glenn on February 20, 1962, in the Friendship 7 , making three full orbits before reentering. Glenn had to fly parts of his final two orbits manually due to an autopilot malfunction. The sixth and final Mercury mission was flown by Gordon Cooper in May 1963, performing 22 orbits over 34 hours in
1890-583: A permanently manned space station and to do it within a decade. In 1985, NASA proposed the Space Station Freedom , which both the agency and President Reagan intended to be an international program. While this would add legitimacy to the program, there were concerns within NASA that the international component would dilute its authority within the project, having never been willing to work with domestic or international partners as true equals. There
2025-650: A possible source of antimatter at the center of the Milky Way and observing that the majority of gamma-ray bursts occur outside of the Milky Way galaxy. The Chandra X-ray Observatory was launched from the Columbia on STS-93 in 1999, observing black holes, quasars , supernova , and dark matter . It provided critical observations on the Sagittarius A* black hole at the center of the Milky Way galaxy and
2160-412: A program for ISS services in the mid 1990s entitled "Alt Access" for Alternate Access. While NASA funded Alt Access no further than preliminary studies, this program convinced numerous entrepreneurs that ISS could emerge as a significant market opportunity. After years of keeping orbital transport for human spaceflight in-house, NASA concluded that firms in a free market could develop and operate such
2295-644: A propellant tanker potentially beginning in the mid-2020s. ACES was not funded, but some of the ideas were used in the Centaur stage of the Vulcan Centaur rocket. Beyond theoretical studies, since at least 2017, SpaceX has undertaken funded development of an interplanetary set of technologies. While the interplanetary mission architecture consists of a combination of several elements that are considered by SpaceX to be key to making long-duration beyond Earth orbit (BEO) spaceflights possible by reducing
2430-502: A single LEO depot in an ISS -inclination orbit (51 degrees) to dispatch nine spacecraft to "nine different interplanetary targets [where the depot need not] perform any phasing maneuvers to align with any of the departure asymptotes ... [including enabling] extending the economic benefits of dedicated smallsat launch to interplanetary missions." Boil-off of cryogenic propellants in space may be mitigated by both technological solutions as well as system-level planning and design . From
2565-540: A space station since the agency was created. In 1973, following the end of the Apollo lunar missions, NASA launched its first space station, Skylab , on the final launch of the Saturn V. Skylab reused a significant amount of Apollo and Saturn hardware, with a repurposed Saturn V third stage serving as the primary module for the space station. Damage to Skylab during its launch required spacewalks to be performed by
2700-646: A specific rocket or a heavy lift such as the SLS to support multiple destinations such as the Moon, Lagrange points, asteroids, and Mars. NASA studies in 2011 showed lower cost and faster alternatives than the Heavy Lift Launch System and listed the following advantages: Propellant depots were proposed as part of the Space Transportation System (along with nuclear "tugs" to take payloads from LEO to other destinations) in
2835-564: A suitable launcher. In May 2006, NASA selected six semifinalist proposals for further evaluation: SpaceX , Andrews Space , Transformational Space Corp. , Rocketplane Kistler ("RpK"), Spacehab , and SpaceDev . On 18 August 2006, NASA's Exploration Systems Mission Directorate (ESMD) announced that SpaceX and Rocketplane Kistler won Phase I of the COTS program. NASA planned to engage winners in funded Space Act agreements through 2010. On 8 November 2006 RpK and ATK announced that ATK would become
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#17327753946212970-470: A system more efficiently and affordably than a government bureaucracy . The then NASA Administrator Michael D. Griffin stated that without affordable Commercial Orbital Transportation Services (COTS), the agency will not have enough funds remaining to achieve the objectives of the Vision for Space Exploration . In November 2005, Dr. Griffin articulated that: Furthermore, if such services were unavailable by
3105-399: A technical perspective: for a propellant depot with passive insulation system to effectively store cryogenic fluids, boil-off caused by heating from solar and other sources must be mitigated, eliminated, or used for economic purposes. For non-cryogenic propellants, boil-off is not a significant design problem. Boil-off rate is governed by heat leakage and by the quantity of propellant in
3240-438: A testbed for demonstrating a number of technologies needed for cryogenic propellant depots, with several small-scale demonstrations planned for 2012–2014. As of August 2011 , ULA said this mission could launch as soon as 2012 if funded. The ULA CRYOTE small-scale demonstrations are intended to lead to a ULA large-scale cryo-sat flagship technology demonstration in 2015. The Future In-Space Operations (FISO) Working Group,
3375-470: A three-burn orbital transfer is used, which includes a plane change at apogee in a highly-elliptical phasing orbit, in which the incremental delta-v is small—typically less than five percent of the total delta-v—"enabling departures to deep-space destinations [taking] advantage of a depot in LEO" and providing frequent departure opportunities. More specifically, the 3-burn departure strategy has been shown to enable
3510-479: A total useful propellant mass of 30 mT. ... the described depot would have a boil-off rate approaching 0.1 percent per day, consisting entirely of hydrogen." In September 2010, ULA released a Depot-Based Space Transportation Architecture concept to propose propellant depots that could be used as way-stations for other spacecraft to stop and refuel—either in low Earth orbit (LEO) for beyond-LEO missions, or at Lagrangian point L 2 for interplanetary missions—at
3645-425: A transfer stage headed to the Moon, Mars, or possibly a geosynchronous orbit. Since all or a fraction of the transfer stage propellant can be off-loaded, the separately launched spacecraft with payload and/or crew could have a larger mass or use a smaller launch vehicle. With a LEO depot or tanker fill, the size of the launch vehicle can be reduced and the flight rate increased—or, with a newer mission architecture where
3780-431: Is a passive depot with additional power and refrigeration equipment/cryocoolers to reduce or eliminate propellant boiloff. Other active cryogenic depot concepts include electrically powered attitude control equipment to conserve fuel for the end payload. In the heavy lift architecture, propellant, which can be two-thirds or more of the total mission mass, is accumulated in fewer launches and possibly shorter time frame than
3915-590: The Faith 7 . The Mercury Program was wildly recognized as a resounding success, achieving its objectives to orbit a human in space, develop tracking and control systems, and identify other issues associated with human spaceflight. While much of NASA's attention turned to space, it did not put aside its aeronautics mission. Early aeronautics research attempted to build upon the X-1's supersonic flight to build an aircraft capable of hypersonic flight . The North American X-15
4050-480: The 2009 Augustine report to NASA , which "examined the [then] current concepts for in-space refueling." The report determined there are essentially two approaches to refueling a spacecraft in LEO: Both approaches were considered feasible with 2009 spaceflight technology, but anticipated that significant further engineering development and in-space demonstration would be required before missions could depend on
4185-604: The AIAA Space 2010 conference. The concept proposes that waste gaseous hydrogen —an inevitable byproduct of long-term liquid hydrogen storage in the radiative heat environment of space —would be usable as a monopropellant in a solar-thermal propulsion system . The waste hydrogen would be productively used for both orbital stationkeeping and attitude control , as well as providing limited propellant and thrust to use for orbital maneuvers to better rendezvous with other spacecraft that would be inbound to receive fuel from
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4320-756: The Army Ballistic Missile Agency would launch Explorer 1 , America's first satellite, on February 1, 1958. The Eisenhower Administration decided to split the United States' military and civil spaceflight programs, which were organized together under the Defense Department 's Advanced Research Projects Agency . NASA was established on July 29, 1958, with the signing of the National Aeronautics and Space Act and it began operations on October 1, 1958. As
4455-803: The Bell X-1 in a joint program with the U.S. Air Force . NACA's interest in space grew out of its rocketry program at the Pilotless Aircraft Research Division. The Soviet Union's launch of Sputnik 1 ushered in the Space Age and kicked off the Space Race . Despite NACA's early rocketry program, the responsibility for launching the first American satellite fell to the Naval Research Laboratory 's Project Vanguard , whose operational issues ensured
4590-742: The Big Bang , through the James Webb Space Telescope , the four Great Observatories , and associated programs. The Launch Services Program oversees launch operations for its uncrewed launches . NASA traces its roots to the National Advisory Committee for Aeronautics (NACA). Despite being the birthplace of aviation, by 1914 the United States recognized that it was far behind Europe in aviation capability. Determined to regain American leadership in aviation,
4725-622: The Big Bang . The James Webb Space Telescope , named after the NASA administrator who lead the Apollo program, is an infrared observatory launched in 2021. The James Webb Space Telescope is a direct successor to the Hubble Space Telescope, intended to observe the formation of the first galaxies. Other space telescopes include the Kepler space telescope , launched in 2009 to identify planets orbiting extrasolar stars that may be Terran and possibly harbor life. The first exoplanet that
4860-981: The Commercial Crew Program , and oversees the development of the Orion spacecraft and the Space Launch System for the lunar Artemis program . NASA's science division is focused on better understanding Earth through the Earth Observing System ; advancing heliophysics through the efforts of the Science Mission Directorate 's Heliophysics Research Program; exploring bodies throughout the Solar System with advanced robotic spacecraft such as New Horizons and planetary rovers such as Perseverance ; and researching astrophysics topics, such as
4995-797: The Environmental Science Services Administration on a series of weather satellites and the agency launched its experimental Applications Technology Satellites into geosynchronous orbit. NASA's first dedicated Earth observation satellite, Landsat , was launched in 1972. This led to NASA and the National Oceanic and Atmospheric Administration jointly developing the Geostationary Operational Environmental Satellite and discovering Ozone depletion . NASA had been pursuing spaceplane development since
5130-691: The Europa and observed that the moon may hold ice or liquid water. A joint NASA- European Space Agency - Italian Space Agency mission, Cassini–Huygens , was sent to Saturn 's moon Titan , which, along with Mars and Europa, are the only celestial bodies in the Solar System suspected of being capable of harboring life. Cassini discovered three new moons of Saturn and the Huygens probe entered Titan's atmosphere. The mission discovered evidence of liquid hydrocarbon lakes on Titan and subsurface water oceans on
5265-784: The Johnson Space Center as the lead center for the design, development, and manufacturing of the Space Shuttle orbiter , while the Marshall Space Flight Center would lead the development of the launch system. NASA's series of lifting body aircraft, culminating in the joint NASA-U.S. Air Force Martin Marietta X-24 , directly informed the development of the Space Shuttle and future hypersonic flight aircraft. Official development of
5400-476: The Lagrange Points and Phobos depots could be performed using Solar electric propulsion (SEP) tugs. Two missions are currently under development or proposed to support propellant depot refilling. In 1962, S.T. Demetriades proposed a method for refilling by collecting atmospheric gases. Moving in low Earth orbit , at an altitude of around 120 km, Demetriades' proposed depot extracts air from
5535-664: The Mars Global Surveyor orbiter and Mars Pathfinder , deploying the first Mars rover, Sojourner . During the early 2000s, the 2001 Mars Odyssey orbiter reached the planet and in 2004 the Sprit and Opportunity rovers landed on the Red Planet. This was followed in 2005 by the Mars Reconnaissance Orbiter and 2007 Phoenix Mars lander. The 2012 landing of Curiosity discovered that
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5670-614: The Orbiting Geophysical Observatory in the 1960s and 1970s to look down at Earth and observe its interactions with the Sun. The Uhuru satellite was the first dedicated x-ray telescope, mapping 85% of the sky and discovering a large number of black holes . Launched in the 1990s and early 2000s, the Great Observatories program are among NASA's most powerful telescopes. The Hubble Space Telescope
5805-658: The STS-1 mission, designed to serve as a flight test for the new spaceplane. NASA intended for the Space Shuttle to replace expendable launch systems like the Air Force's Atlas , Delta , and Titan and the European Space Agency 's Ariane . The Space Shuttle's Spacelab payload, developed by the European Space Agency, increased the scientific capabilities of shuttle missions over anything NASA
5940-635: The STS-60 mission in 1994 and the Discovery rendezvoused, but did not dock with, the Russian Mir in the STS-63 mission. This was followed by Atlantis' STS-71 mission where it accomplished the initial intended mission for the Space Shuttle, docking with a space station and transferring supplies and personnel. The Shuttle- Mir program would continue until 1998, when a series of orbital accidents on
6075-477: The Space Race when the Soviet Union gave up its lunar ambitions. As the first human to step on the surface of the Moon, Neil Armstrong uttered the now famous words: That's one small step for man, one giant leap for mankind. NASA would conduct six total lunar landings as part of the Apollo program, with Apollo 17 concluding the program in 1972. Wernher von Braun had advocated for NASA to develop
6210-620: The Space Shuttle began in 1972, with Rockwell International contracted to design the orbiter and engines, Martin Marietta for the external fuel tank , and Morton Thiokol for the solid rocket boosters . NASA acquired six orbiters: the Enterprise , Columbia , Challenger , Discovery , Atlantis , and Endeavour The Space Shuttle program also allowed NASA to make major changes to its Astronaut Corps . While almost all previous astronauts were Air Force or Naval test pilots,
6345-588: The SpaceX Starship , and then after refilling on orbit by multiple Starship tankers, provide the large amount of energy required to put the spacecraft onto an interplanetary trajectory. The Starship tanker is designed to transport approximately 100 tonnes (220,000 lb) of propellant to low Earth orbit. In April 2021, NASA selected the SpaceX Lunar Starship with in-orbit refueling for their initial lunar human landing system. Because
6480-620: The United States Congress created the Aviation Section of the U.S. Army Signal Corps in 1914 and established NACA in 1915 to foster aeronautical research and development. Over the next forty years, NACA would conduct aeronautical research in support of the U.S. Air Force , U.S. Army , U.S. Navy , and the civil aviation sector. After the end of World War II , NACA became interested in the possibilities of guided missiles and supersonic aircraft, developing and testing
6615-405: The inner planets . Despite these successes, Congress was unwilling to fund further interplanetary missions and NASA Administrator James Webb suspended all future interplanetary probes to focus resources on the Apollo program. Following the conclusion of the Apollo program, NASA resumed launching interplanetary probes and expanded its space science program. The first planet tagged for exploration
6750-501: The on-orbit demonstrations. The post-spacecraft mission extension ran 2.4 hours before executing the deorbit burn . NASA's Launch Services Program is working on an ongoing slosh fluid dynamics experiments with partners called CRYOTE. As of 2010 , ULA is also planning additional in-space laboratory experiments to further develop cryogenic fluid management technologies using the Centaur upper stage after primary payload separation. Named CRYOTE, or CRYogenic Orbital TEstbed, it will be
6885-504: The "CRYOGENIC Propellant STorage And Transfer (CRYOSTAT) Mission". The CRYOSTAT vehicle was expected to be launched to LEO in 2015. The CRYOSTAT architecture comprises technologies in the following categories: The "Simple Depot" mission was proposed by NASA in 2011 as a potential first PTSD mission, with launch no earlier than 2015, on an Atlas V 551 . Simple Depot would use the "used" (nearly-emptied) Centaur upper stage LH2 tank for long-term storage of LO2 while LH2 would be stored in
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#17327753946217020-405: The $ 12 billion contract for the Orion spacecraft , the $ 800 million COTS investment resulted in "two new U.S. medium-class launch vehicles and two automated cargo spacecraft". After the conclusion of the COTS program, NASA shifted towards fixed-price contracts for crew and cargo services. While the approach has significantly lowered costs for NASA, companies other than SpaceX have struggled under
7155-524: The 1960s, blending the administration's dual aeronautics and space missions. NASA viewed a spaceplane as part of a larger program, providing routine and economical logistical support to a space station in Earth orbit that would be used as a hub for lunar and Mars missions. A reusable launch vehicle would then have ended the need for expensive and expendable boosters like the Saturn V . In 1969, NASA designated
7290-679: The 44 commercial companies that contracted with NASA to deploy their satellites to return to expendable launch vehicles. When the Space Shuttle returned to flight with the STS-26 mission, it had undergone significant modifications to improve its reliability and safety. Following the collapse of the Soviet Union, the Russian Federation and United States initiated the Shuttle- Mir program . The first Russian cosmonaut flew on
7425-497: The 52nd AAS Annual Meeting in Houston, Texas, November 2005, that "at a conservatively low government price of $ 10,000 per kg in LEO, 250 MT of fuel for two missions per year is worth $ 2.5 billion, at government rates." In the depot-centric architecture, the depot is filled by tankers, and then the propellant is transferred to an upper stage prior to orbit insertion, similar to a gas station filled by tankers for automobiles. By using
7560-630: The Air Force as the military space lead. Plans for human spaceflight began in the U.S. Armed Forces prior to NASA's creation. The Air Force's Man in Space Soonest project formed in 1956, coupled with the Army's Project Adam, served as the foundation for Project Mercury . NASA established the Space Task Group to manage the program, which would conduct crewed sub-orbital flights with the Army's Redstone rockets and orbital flights with
7695-501: The Air Force's Atlas launch vehicles. While NASA intended for its first astronauts to be civilians, President Eisenhower directed that they be selected from the military. The Mercury 7 astronauts included three Air Force pilots, three Navy aviators, and one Marine Corps pilot. On May 5, 1961, Alan Shepard became the first American to enter space, performing a suborbital spaceflight in the Freedom 7 . This flight occurred less than
7830-410: The Apollo program. Despite attacks on the goal of landing astronauts on the Moon from the former president Dwight Eisenhower and 1964 presidential candidate Barry Goldwater , President Kennedy was able to protect NASA's growing budget, of which 50% went directly to human spaceflight and it was later estimated that, at its height, 5% of Americans worked on some aspect of the Apollo program. Mirroring
7965-685: The Army Ballistic Missile Agency's original Saturn I . The Apollo spacecraft was designed and built by North American Aviation , while the Apollo Lunar Module was designed and built by Grumman . To develop the spaceflight skills and equipment required for a lunar mission, NASA initiated Project Gemini . Using a modified Air Force Titan II launch vehicle, the Gemini capsule could hold two astronauts for flights of over two weeks. Gemini pioneered
8100-399: The COTS developed vehicles. COTS employed Space Act Agreements with milestone-based payments, while CRS utilizes binding contracts with strict performance obligations. The Commercial Crew Development (CCDev) program, focusing on crew transportation, is similar to COTS and, along with CRS, falls under NASA's Commercial Crew and Cargo Program Office (C3PO). Unlike any previous NASA project,
8235-421: The COTS program including the controlling of the development program using Space Act Agreements (SAA), with lessons for future programs. More than twenty organizations had submitted COTS proposals by March 2006. NASA received new COTS proposals from at least seven firms by 21 November 2007. On 22 December 2008, NASA stated they would discuss the contract selection to provide commercial cargo resupply services for
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#17327753946218370-426: The Department of Defense's program management concept using redundant systems in building the first intercontinental ballistic missiles, NASA requested the Air Force assign Major General Samuel C. Phillips to the space agency where he would serve as the director of the Apollo program. Development of the Saturn V rocket was led by Wernher von Braun and his team at the Marshall Space Flight Center , derived from
8505-419: The International Space Station. NASA announced the awarding of contracts to both SpaceX and Orbital Sciences Corporation in a press conference on 23 December 2008. The contracts include a minimum of 20 missions, 12 missions for SpaceX ($ 1.6 Billion) and 8 missions for Orbital Sciences ($ 1.9 Billion). PlanetSpace submitted a protest to the Government Accountability Office after receiving a NASA debriefing on
8640-439: The Keplar space telescope confirmed was Kepler-22b , orbiting within the habitable zone of its star. NASA also launched a number of different satellites to study Earth, such as Television Infrared Observation Satellite (TIROS) in 1960, which was the first weather satellite. NASA and the United States Weather Bureau cooperated on future TIROS and the second generation Nimbus program of weather satellites. It also worked with
8775-448: The Martian interior. The 2021 Perseverance rover carried the first extraplanetary aircraft, a helicopter named Ingenuity . NASA also launched missions to Mercury in 2004, with the MESSENGER probe demonstrating as the first use of a solar sail . NASA also launched probes to the outer Solar System starting in the 1960s. Pioneer 10 was the first probe to the outer planets, flying by Jupiter , while Pioneer 11 provided
8910-402: The Moon and going to Mars. Embracing this approach, NASA's Commercial Crew Program started by contracting cargo delivery to the International Space Station and flew its first operational contracted mission on SpaceX Crew-1 . This marked the first time since the retirement of the Space Shuttle that NASA was able to launch its own astronauts on an American spacecraft from the United States, ending
9045-404: The Moon and returning him safely to Earth by the end of the 1960s and installed James E. Webb as NASA administrator to achieve this goal. On May 25, 1961, President Kennedy openly declared this goal in his "Urgent National Needs" speech to the United States Congress, declaring: I believe this Nation should commit itself to achieving the goal, before this decade is out, of landing a man on
9180-427: The Moon and returning him safely to Earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish. Kennedy gave his " We choose to go to the Moon " speech the next year, on September 12, 1962 at Rice University , where he addressed the nation hoping to reinforce public support for
9315-409: The Russians be included. In 1993, the Clinton Administration announced that the Space Station Freedom would become the International Space Station in an agreement with the Russian Federation. This allowed the Russians to maintain their space program through an infusion of American currency to maintain their status as one of the two premier space programs. While the United States built and launched
9450-507: The Russians to fly to the International Space Station for four days, despite the opposition of NASA to the idea. Advocates of this new commercial approach for NASA included former astronaut Buzz Aldrin , who remarked that it would return NASA to its roots as a research and development agency, with commercial entities actually operating the space systems. Having corporations take over orbital operations would also allow NASA to focus all its efforts on deep space exploration and returning humans to
9585-426: The Simple Depot LH2 module, which would be launched with only ambient-temperature gaseous Helium in it. The SD LH2 tank was to be 3 metres (9.8 ft) diameter and 16 metres (52 ft) long, 110 cubic metres (3,900 cu ft) in volume, and store 5 mT of LH2. "At a useful mixture ratio (MR) of 6:1 this quantity of LH2 can be paired with 25.7 mT of LO2, allowing for 0.7 mT of LH2 to be used for vapor cooling, for
9720-422: The Solar System. Mars has long been a planet of intense fascination for NASA, being suspected of potentially having harbored life. Mariner 5 was the first NASA spacecraft to flyby Mars, followed by Mariner 6 and Mariner 7 . Mariner 9 was the first orbital mission to Mars. Launched in 1975, Viking program consisted of two landings on Mars in 1976. Follow-on missions would not be launched until 1996, with
9855-633: The Space Shuttle Columbia disaster in 2003, NASA was forced to rely on Russian Soyuz launches for its astronauts and the 2011 retirement of the Space Shuttle accelerated the station's completion. In the 1980s, right after the first flight of the Space Shuttle, NASA started a joint program with the Department of Defense to develop the Rockwell X-30 National Aerospace Plane. NASA realized that
9990-418: The Space Shuttle allowed NASA to begin recruiting more non-military scientific and technical experts. A prime example is Sally Ride , who became the first American woman to fly in space on STS-7 . This new astronaut selection process also allowed NASA to accept exchange astronauts from U.S. allies and partners for the first time. The first Space Shuttle flight occurred in 1981, when the Columbia launched on
10125-514: The Space Shuttle and expand space exploration beyond low Earth orbit. Constellation was intended to use a significant amount of former Space Shuttle equipment and return astronauts to the Moon. This program was canceled by the Obama Administration . Former astronauts Neil Armstrong , Gene Cernan , and Jim Lovell sent a letter to President Barack Obama to warn him that if the United States did not get new human spaceflight ability,
10260-554: The Space Shuttle began flying, selling it as an orbital laboratory, repair station, and a jumping off point for lunar and Mars missions. NASA found a strong advocate in President Ronald Reagan , who declared in a 1984 speech: America has always been greatest when we dared to be great. We can reach for greatness again. We can follow our dreams to distant stars, living and working in space for peaceful, economic, and scientific gain. Tonight I am directing NASA to develop
10395-686: The Space Shuttle, while a massive technological accomplishment, would not be able to live up to all its promises. Designed to be a single-stage-to-orbit spaceplane, the X-30 had both civil and military applications. With the end of the Cold War , the X-30 was canceled in 1992 before reaching flight status. Following the Space Shuttle Columbia disaster in 2003, President Bush started the Constellation program to smoothly replace
10530-483: The Space Shuttle. Due to technical challenges, the spacecraft was cancelled in 2001. Despite this, it was the first time a commercial space company directly expended a significant amount of its resources into spacecraft development. The advent of space tourism also forced NASA to challenge its assumption that only governments would have people in space. The first space tourist was Dennis Tito , an American investment manager and former aerospace engineer who contracted with
10665-580: The Space Station Freedom was controversial, with much of the debate centering on cost. Several redesigns to reduce cost were conducted in the early 1990s, stripping away much of its functions. Despite calls for Congress to terminate the program, it continued, in large part because by 1992 it had created 75,000 jobs across 39 states. By 1993, President Bill Clinton attempted to significantly reduce NASA's budget and directed costs be significantly reduced, aerospace industry jobs were not lost, and
10800-602: The U.S. risked become a second or third-rate space power. As early as the Reagan Administration, there had been calls for NASA to expand private sector involvement in space exploration rather than do it all in-house. In the 1990s, NASA and Lockheed Martin entered into an agreement to develop the Lockheed Martin X-33 demonstrator of the VentureStar spaceplane, which was intended to replace
10935-461: The U.S. space development effort a distinct civilian orientation, emphasizing peaceful applications in space science . It has since led most of America's space exploration programs, including Project Mercury , Project Gemini , the 1968–1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle . Currently, NASA supports the International Space Station (ISS) along with
11070-536: The US's premier aeronautics agency, NACA formed the core of NASA's new structure by reassigning 8,000 employees and three major research laboratories. NASA also proceeded to absorb the Naval Research Laboratory's Project Vanguard, the Army's Jet Propulsion Laboratory (JPL), and the Army Ballistic Missile Agency under Wernher von Braun . This left NASA firmly as the United States' civil space lead and
11205-533: The announcement date set to 7 February. Several sources later suggested that Boeing and not Andrews was a final contestant. On 19 February 2008, the second round selection was made to Orbital Sciences Corporation , for the Cygnus spacecraft . NASA's selection statement showed that Orbital beat Boeing on expected lower costs and the added benefit of a new medium lift launcher Taurus II with Andrews, PlanetSpace and Spacehab being eliminated on funding concerns. Following
11340-410: The beyond-Earth-orbit spacecraft also serves as the second stage, can facilitate much larger payloads—which may reduce the total launch costs since the fixed costs are spread over more flights and fixed costs are usually lower with smaller launch vehicles. A depot could also be placed at Earth-Moon Lagrange point 1 (EML-1) or behind the Moon at EML-2 to reduce costs to travel to the Moon or Mars. Placing
11475-571: The cleanup of space debris . In August 2011, NASA made a significant contractual commitment to the development of propellant depot technology by funding four aerospace companies to "define demonstration missions that would validate the concept of storing cryogenic propellants in space to reduce the need for large launch vehicles for deep-space exploration." These study contracts for storing/transferring cryogenic propellants and cryogenic depots were signed with Analytical Mechanics Associates , Boeing , Lockheed Martin and Ball Aerospace . Each company
11610-525: The companies to develop their proposed vehicles. On 22 October 2007, NASA solicited proposals for the $ 175 million in unawarded first round funds. Some of the new contenders who entered before the deadline in November 2007 for the funding were Spacehab , t/Space , Andrews Space , PlanetSpace and SpaceDev . In January 2008 industry sources claimed that the field had been downselected to four; Spacehab, Andrews Space, PlanetSpace and Orbital Sciences, with
11745-731: The contract to Kistler after hearing that the Government Accountability Office planned to issue a ruling in support of Musk. NASA returned to the planning phase, and this eventually resulted in the COTS competition. Boeing may have submitted a proposal in conjunction with Arianespace to launch the ESA ATV module on a Delta IV rocket. Whereas the ESA launches the ATV on an Ariane 5, the two companies worked together to make this proposal. The ATV can carry up to 7.6 metric tons with
11880-453: The cost per ton delivered to Mars by multiple orders of magnitude over what NASA approaches have achieved, refilling of propellants in orbit is one of the four key elements. In a novel mission architecture, the SpaceX design intends to enable the long-journey spacecraft to expend almost all of its propellant load during the launch to low Earth orbit while it serves as the second stage of
12015-631: The depot centric architecture. Typically the transfer stage is filled directly and no depot is included in the architecture. For cryogenic vehicles and cryogenic depots, additional boiloff mitigation equipment is typically included on the transfer stage, reducing payload fraction and requiring more propellant for the same payload unless the mitigation hardware is expended. Heavy Lift is compared with using Commercial Launch and Propellant Depots in this power point by Dr. Alan Wilhite given at FISO Telecon. Both theoretical studies and funded development projects that are currently underway aim to provide insight into
12150-465: The depot is in a different orbital plane than the target orbit. The delta-v to make the necessary plane change is typically extremely high. On the other hand, depots are typically proposed for exploration missions, where the change over time of the depot's orbit can be chosen to align with the departure vector. This allows one well-aligned departure time minimizing fuel use that requires a very precisely-timed departure. Less efficient departure times from
12285-601: The depot. As part of the Depot-Based Space Transportation Architecture, ULA has proposed the Advanced Common Evolved Stage (ACES) upper stage rocket . ACES hardware is designed from the start as an in-space propellant depot that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or interplanetary missions, and to provide the high-energy technical capacity for
12420-631: The end of 2010, NASA would have been forced to purchase orbital transportation services on foreign spacecraft such as the Russian Federal Space Agency 's Soyuz and Progress spacecraft , the European Space Agency 's Automated Transfer Vehicle , or the Japan Aerospace Exploration Agency 's H-II Transfer Vehicle since NASA's own Crew Exploration Vehicle , since refocused, would not have been ready until 2014. In 2007 NASA asserted that once COTS
12555-450: The feasibility of propellant depots. Studies have shown that a depot-centric architecture with smaller launch vehicles could be US$ 57 billion less expensive than a heavy-lift architecture over a 20-year time frame. The cost of large launch vehicles is so high that a depot able to hold the propellant lifted by two or more medium-sized launch vehicles may be cost effective and support more payload mass on beyond-Earth orbit trajectories. In
12690-420: The first close up view of the planet. Both probes became the first objects to leave the Solar System. The Voyager program launched in 1977, conducting flybys of Jupiter and Saturn , Neptune , and Uranus on a trajectory to leave the Solar System. The Galileo spacecraft, deployed from the Space Shuttle flight STS-34 , was the first spacecraft to orbit Jupiter, discovering evidence of subsurface oceans on
12825-515: The first crew to make it habitable and operational. Skylab hosted nine missions and was decommissioned in 1974 and deorbited in 1979, two years prior to the first launch of the Space Shuttle and any possibility of boosting its orbit. In 1975, the Apollo–Soyuz mission was the first ever international spaceflight and a major diplomatic accomplishment between the Cold War rivals, which also marked
12960-402: The first humans to see the Earth as a globe in space, the first to witness an Earthrise , and the first to see and manually photograph the far side of the Moon. The first lunar landing was conducted by Apollo 11. Commanded by Neil Armstrong with astronauts Buzz Aldrin and Michael Collins , Apollo 11 was one of the most significant missions in NASA's history, marking the end of
13095-657: The first phase of COTS prove successful. On 22 May 2012, Bill Gerstenmaier confirmed that NASA was no longer purchasing any cargo resupply services from Russia and would rely solely on the American CRS vehicles, the SpaceX Dragon and Orbital Sciences' Cygnus ; with the exception of a few vehicle-specific payloads delivered on the European ATV and the Japanese HTV . In February 2004, NASA awarded
13230-524: The fixed-price system, with some refusing to bid and others experiencing large losses on contracts. COTS contracts were awarded to SpaceX and Rocketplane Kistler , but the latter's agreement was terminated due to insufficient progress. Orbital Sciences Corporation replaced Rocketplane Kistler in the program in 2008. COTS differs from the Commercial Resupply Services (CRS) program, which procured cargo delivery services using
13365-423: The fringes of the atmosphere, compresses and cools it, and extracts liquid oxygen. The remaining nitrogen is used as propellant for a nuclear-powered magnetohydrodynamic engine, which maintains the orbit, compensating for atmospheric drag . This system was called "PROFAC" ( PROpulsive Fluid ACcumulator ). There are, however, safety concerns with placing a nuclear reactor in low Earth orbit. Demetriades' proposal
13500-464: The large specific impulse possible, but must carefully consider a problem called "boil off," or the evaporation of the cryogenic propellant. The boil off from only a few days of delay may not allow sufficient fuel for higher orbit injection, potentially resulting in a mission abort. Lunar or Mars missions will require weeks to months to accumulate tens of thousands to hundreds of thousands of kilograms of propellant, so additional equipment may be required on
13635-451: The last flight of the Apollo capsule. Flown in 1975, a U.S. Apollo spacecraft docked with a Soviet Soyuz capsule. During the 1960s, NASA started its space science and interplanetary probe program. The Mariner program was its flagship program, launching probes to Venus , Mars , and Mercury in the 1960s. The Jet Propulsion Laboratory was the lead NASA center for robotic interplanetary exploration, making significant discoveries about
13770-672: The lead contractor for the K-1. NASA terminated the COTS agreement with RpK in September 2007 after NASA warned RpK that it had failed to raise sufficient private funding by 31 July 2007 deadline, freeing up $ 175 million from the COTS budget to be awarded to another company or companies. By 18 June 2007, NASA had signed separate non-reimbursable Space Act Agreements with three additional firms, Constellation Services International (CSI), SpaceDev and Spacehab. These agreements included no financial support, however NASA agreed to share information to help
13905-547: The lifetime of satellites that have nearly consumed their orbital maneuvering fuel and are likely placed in a geosynchronous orbit. The spacecraft would conduct a space rendezvous with the depot, or vice versa , and then transfer propellant to be used for subsequent orbital maneuvers . In 2011, Intelsat showed interest in an initial demonstration mission to refuel several satellites in geosynchronous orbit , but all plans have been since scrapped. A low Earth orbit (LEO) depot's primary function would be to provide propellant to
14040-413: The lowest price takes place, and it may also enable an economy of scale by permitting existing rockets to fly more often to refuel the depot. If used in conjunction with a mining facility on the moon , water or propellant could be exported back to the depot, further reducing the cost of propellant. An exploration program based on a depot architecture could be less expensive and more capable, not needing
14175-515: The majority of the International Space Station, Russia, Canada, Japan, and the European Space Agency all contributed components. Despite NASA's insistence that costs would be kept at a budget of $ 17.4, they kept rising and NASA had to transfer funds from other programs to keep the International Space Station solvent. Ultimately, the total cost of the station was $ 150 billion, with the United States paying for two-thirds.Following
14310-517: The maturity of the refrigeration equipment/cryocoolers, and the power and mass required for reduced or zero boiloff depots with refrigeration. Transfer of liquid propellants in microgravity is complicated by the uncertain distribution of liquid and gasses within a tank. Propellant settling at an in-space depot is thus more challenging than in even a slight gravity field. ULA plans to use the DMSP -18 mission to flight-test centrifugal propellant settling as
14445-553: The mid-1960s. In October 2009, the U.S. Air Force and United Launch Alliance (ULA) performed an experimental on-orbit demonstration on a modified Centaur upper stage on the DMSP-18 launch to improve "understanding of propellant settling and slosh , pressure control, RL10 chilldown and RL10 two-phase shutdown operations." "The light weight of DMSP-18 allowed 12,000 pounds (5,400 kg) of remaining liquid O 2 and liquid H 2 propellant, 28% of Centaur's capacity," for
14580-634: The moon of Enceladus , which could harbor life. Finally launched in 2006, the New Horizons mission was the first spacecraft to visit Pluto and the Kuiper Belt . Beyond interplanetary probes, NASA has launched many space telescopes . Launched in the 1960s, the Orbiting Astronomical Observatory were NASA's first orbital telescopes, providing ultraviolet, gamma-ray, x-ray, and infrared observations. NASA launched
14715-486: The much higher temperature cryogenic fluid of liquid oxygen would boil off much less, about 0.016% per day (0.49% per month). It is possible to achieve zero boil-off (ZBO) with cryogenic propellant storage using an active thermal control system. Tests conducted at the NASA Lewis Research Center 's Supplemental Multilayer Insulation Research Facility (SMIRF) over the summer of 1998 demonstrated that
14850-404: The original $ 500M Space Act Agreement, an additional $ 288M in "augmentation" funding was awarded to the two contractors before the demonstration flights. The COTS program was successfully concluded in November 2013 after two companies, SpaceX and Orbital Sciences, designed, built and launched "a pair of new spacecraft on rockets that also were newly designed". NASA has published its own history of
14985-454: The outcome of the award. On 22 April 2009 GAO publicly released its decision to deny the protest. NASA The National Aeronautics and Space Administration ( NASA / ˈ n æ s ə / ) is an independent agency of the U.S. federal government responsible for the civil space program , aeronautics research, and space research. Established in 1958 , it succeeded the National Advisory Committee for Aeronautics (NACA) to give
15120-430: The propellant. By using several tanker rockets the tankers can be smaller than the depot and larger than the spacecraft they are intended to resupply. Short range chemical propulsion tugs belonging to the depot may be used to simplify docking tanker rockets and large vehicles like Mars Transfer Vehicles. Transfers of propellant between a LEO depot, reachable by rockets from Earth, and the possible deep space ones such as at
15255-522: The proposed spacecraft were intended to be owned and financed primarily by the companies themselves and were designed to serve both U.S. government agencies and commercial customers. NASA will contract for missions as its needs become clear. This was more challenging than existent commercial space transportation because it required precision orbit insertion , rendezvous and possibly docking with another spacecraft. The private spaceflight vendors were competing for four specific service areas: NASA explored
15390-625: The radiation levels on Mars were equal to those on the International Space Station , greatly increasing the possibility of Human exploration, and observed the key chemical ingredients for life to occur. In 2013, the Mars Atmosphere and Volatile Evolution ( MAVEN ) mission observed the Martian upper atmosphere and space environment and in 2018, the Interior exploration using Seismic Investigations Geodesy, and Heat Transport ( InSight ) studied
15525-798: The same depot to the same destination exist before and after the well-aligned opportunity, but more research is required to show whether the efficiency falls off quickly or slowly. By contrast, launching directly in only one launch from the ground without orbital refueling or docking with another craft already on orbit offers daily launch opportunities though it requires larger and more expensive launchers. The restrictions on departure windows arise because low earth orbits are susceptible to significant perturbations; even over short periods they are subject to nodal regression and, less importantly, precession of perigee. Equatorial depots are more stable but also more difficult to reach. New approaches have been discovered for LEO to interplanetary orbital transfers where
15660-507: The satellites were repaired and relaunched. Despite ushering in a new era of spaceflight, where NASA was contracting launch services to commercial companies, the Space Shuttle was criticized for not being as reusable and cost-effective as advertised. In 1986, Challenger disaster on the STS-51L mission resulted in the loss of the spacecraft and all seven astronauts on launch, grounding the entire space shuttle fleet for 36 months and forced
15795-676: The separation of dark and regular matter during galactic collisions. Finally, the Spitzer Space Telescope is an infrared telescope launched in 2003 from a Delta II rocket. It is in a trailing orbit around the Sun, following the Earth and discovered the existence of brown dwarf stars . Other telescopes, such as the Cosmic Background Explorer and the Wilkinson Microwave Anisotropy Probe , provided evidence to support
15930-560: The setback caused by the Apollo 1 fire, which killed three astronauts, the program proceeded. Apollo 8 was the first crewed spacecraft to leave low Earth orbit and the first human spaceflight to reach the Moon . The crew orbited the Moon ten times on December 24 and 25, 1968, and then traveled safely back to Earth . The three Apollo 8 astronauts— Frank Borman , James Lovell , and William Anders —were
16065-549: The space shuttle be retired. In 2006, the Space Shuttle returned to flight, conducting several mission to service the Hubble Space Telescope , but was retired following the STS-135 resupply mission to the International Space Station in 2011. NASA never gave up on the idea of a space station after Skylab's reentry in 1979. The agency began lobbying politicians to support building a larger space station as soon as
16200-481: The space station spelled an end to the program. In 2003, a second space shuttle was destroyed when the Columbia was destroyed upon reentry during the STS-107 mission, resulting in the loss of the spacecraft and all seven astronauts. This accident marked the beginning of the retiring of the Space Shuttle program, with President George W. Bush directing that upon the completion of the International Space Station,
16335-403: The tanks. With partially filled tanks, the percentage loss is higher. Heat leakage depends on surface area, while the original mass of propellant in the tanks depends on volume. So by the cube-square law , the smaller the tank, the faster the liquids will boil off. Some propellant tank designs have achieved a liquid hydrogen boil off rate as low as approximately 0.13% per day (3.8% per month) while
16470-413: The technology. Both approaches were seen to offer the potential of long-term life-cycle savings. In 2010 United Launch Alliance (ULA) proposed their Advanced Cryogenic Evolved Stage (ACES) tanker, a concept that dates to work by Boeing in 2006, sized to transport up to 73 tonnes (161,000 lb) of propellant—in early design, a first flight was proposed for no earlier than 2023, with initial usage as
16605-572: The transfer stage or the depot to mitigate boiloff. Non-cryogenic, earth-storable liquid rocket propellants including RP-1 ( kerosene ), hydrazine and nitrogen tetroxide (NTO), and mildly cryogenic, space-storable propellants like liquid methane and liquid oxygen , can be kept in liquid form with less boiloff than the cryogenic fuels, but also have lower specific impulse. Additionally, gaseous or supercritical propellants such as those used by ion thrusters include xenon , argon , and bismuth . Ex-NASA administrator Mike Griffin commented at
16740-491: The type of fuel to be supplied, location, or type of depot which may also include a propellant tanker that delivers a single load to a spacecraft at a specified orbital location and then departs. In-space fuel depots are not necessarily located near or at a space station . Potential users of in-orbit refueling and storage facilities include space agencies , defense ministries and communications satellite or other commercial companies. Satellite servicing depots would extend
16875-579: The use of fuel cells instead of batteries, and conducted the first American spacewalks and rendezvous operations . The Ranger Program was started in the 1950s as a response to Soviet lunar exploration, however most missions ended in failure. The Lunar Orbiter program had greater success, mapping the surface in preparation for Apollo landings and measured Selenography , conducted meteoroid detection, and measured radiation levels. The Surveyor program conducted uncrewed lunar landings and takeoffs, as well as taking surface and regolith observations. Despite
17010-513: The various projects, mission architectures and associated timelines relevant to lunar and Mars exploration and science. Propellant depot An orbital propellant depot is a cache of propellant that is placed in orbit around Earth or another body to allow spacecraft or the transfer stage of the spacecraft to be fueled in space. It is one of the types of space resource depots that have been proposed for enabling infrastructure-based space exploration . Many depot concepts exist depending on
17145-461: Was Venus , sharing many similar characteristics to Earth. First visited by American Mariner 2 spacecraft, Venus was observed to be a hot and inhospitable planet. Follow-on missions included the Pioneer Venus project in the 1970s and Magellan , which performed radar mapping of Venus' surface in the 1980s and 1990s. Future missions were flybys of Venus, on their way to other destinations in
17280-434: Was a joint NASA–U.S. Air Force program, with the hypersonic test aircraft becoming the first non-dedicated spacecraft to cross from the atmosphere to outer space. The X-15 also served as a testbed for Apollo program technologies, as well as ramjet and scramjet propulsion. Escalations in the Cold War between the United States and Soviet Union prompted President John F. Kennedy to charge NASA with landing an American on
17415-683: Was able to previously accomplish. NASA launched its first commercial satellites on the STS-5 mission and in 1984, the STS-41-C mission conducted the world's first on-orbit satellite servicing mission when the Challenger captured and repaired the malfunctioning Solar Maximum Mission satellite. It also had the capability to return malfunctioning satellite to Earth, like it did with the Palapa B2 and Westar 6 satellites. Once returned to Earth,
17550-472: Was also a concern with sharing sensitive space technologies with the Europeans, which had the potential to dilute America's technical lead. Ultimately, an international agreement to develop the Space Station Freedom program would be signed with thirteen countries in 1985, including the European Space Agency member states, Canada , and Japan . Despite its status as the first international space program,
17685-486: Was further refined by Christopher Jones and others In this proposal, multiple collection vehicles accumulate propellant gases at around 120 km altitude, later transferring them to a higher orbit. However, Jones' proposal does require a network of orbital power-beaming satellites , to avoid placing nuclear reactors in orbit. Asteroids can also be processed to provide liquid oxygen. Propellant depots in LEO are of little use for transfer between two low earth orbits when
17820-497: Was launched in 1990 on STS-31 from the Discovery and could view galaxies 15 billion light years away. A major defect in the telescope's mirror could have crippled the program, had NASA not used computer enhancement to compensate for the imperfection and launched five Space Shuttle servicing flights to replace the damaged components. The Compton Gamma Ray Observatory was launched from the Atlantis on STS-37 in 1991, discovering
17955-420: Was operational, it would no longer procure Russian cargo delivery services. NASA anticipates that COTS services to ISS will be necessary through at least 2015. NASA projects at most a half-dozen COTS flights a year that would transport 10 tonnes annually. The NASA Administrator has suggested that space transportation services procurement may be expanded to orbital fuel depots and lunar surface deliveries should
18090-470: Was successfully transferred between two single-purpose designed technology demonstration spacecraft. The Boeing servicing spacecraft ASTRO transferred propellant to the Ball Aerospace serviceable client spacecraft NEXTSat . Since no crew were present on either spacecraft, this was reported as the first autonomous spacecraft-to-spacecraft fluid transfer. After propellant has been transferred to
18225-713: Was to receive US$ 600,000 under the contract. In April 2021, NASA selected the SpaceX Lunar Starship with in-orbit refuelling for their initial lunar human landing system. In 2022, a larger propellant-depot Starship was being planned for Lunar Starship HLS. The Chinese Space Agency (CNSA) performed its first satellite-to-satellite on-orbit refueling test in June 2016. There are a number of design issues with propellant depots, as well as several tasks that have not, to date, been tested in space for on-orbit servicing missions. The design issues include propellant settling and transfer, propellant usage for attitude control and reboost,
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