Chapter 4.0 Current Human Spaceflight Programs
The current U.S. human spaceflight programs are the operational Space Shuttle Program and the U.S. portion of the International Space Station (ISS). The next human spaceflight effort, the Constellation Program, is in development.
4.1 The Space Shuttle
The Commission reviewed long history of the Space Shuttle, its two fatal accidents, and the increasing complexity of missions, especially those since the return to flight in 2005. Early missions were 4 to 7 days and rarely involved a space walk. Current missions are 13 to 14 days and have involved as many as 5 space walks. The Hubble repair mission is typical.
The Shuttle was scheduled for retirement in 2010, and the replacement vehicle was scheduled to arrive in 2012. After four years of development, the Constellation Program does not expect this replacement vehicle to arrive before 2016, at the earliest. Currently, the time between Shuttle missions is averaging 100 days. With six missions remaining, the schedule calls for completion in 2010, an average of only 64 days between flights. The schedule would extend into the middle of 2011 if current prudent safety practices are maintained.
The Committee explored three scenarios for the Shuttle:
- Scenario 1: Prudent Shuttle Fly-Out. As noted, the current Shuttle schedule has little or no margin remaining. Scenario 1 is a likely reflection of reality. It restores margin to the schedule, at a flight rate in line with recent experience, and allocates funds in FY 2011 to support Shuttle operations into that fiscal year. Based on historical data, the Committee believes it is likely that the remaining six flights on the manifest will stretch into the second quarter of 2011, and it is prudent to plan for that occurrence and explicitly include the associated costs in the FY 2011 budget.
- Scenario 2: Short-Term Support for the ISS. Space Shuttle retirement will have an impact on the ISS (described more fully in a subsequent section). Scenario 2 would add one additional Shuttle flight to provide some additional support for the ISS and ease the transition to commercial and international cargo flights. It could enhance early utilization of the ISS, offer an opportunity for providing more spare parts, and enable scientific experiments to be brought back to Earth. This additional Shuttle flight would not replace any of the planned international or commercial resupply flights.
- Scenario 3: Extend Shuttle to 2015 at Minimum Flight Rate. This scenario would extend the Shuttle at a minimum safe flight rate (nominally two flights per year) into FY 2015. Once the Shuttle is retired, the U.S. itself will no longer have the ability to launch astronauts into space, and will have to rely on the Russian Soyuz vehicle. That gap will persist until a new vehicle becomes available to transport crew to low-Earth orbit. Under the current program, the resulting gap is expected to be seven years or more. This scenario, if combined with a new crew launch capability that will be available by the middle of the 2010s, significantly reduces that gap, and retains U.S. ability to deliver astronauts to the ISS.
While the Commission strongly leans toward scenario 1, it acknowledges good reasons for scenario 3, since American access to the International Space Station (ISS) and material support of the ISS are very important.
4.2 The International Space Station
Construction of the International Space Station was begun in 1998 and was scheduled to be completed with an aggressive Shuttle schedule. The Columbia accident suspended construction, and Russia kept the ISS alive until the Shuttle returned in 2005. Construction was slowed by the prudent flight rate and the ISS was completed this year. It is scheduled to be decommissioned in 2015, and splashed into the Pacific Ocean.
It is now acknowledged that such a course would shred the current International Partnership involving the ISS. Further, retirement of the Shuttle puts the ISS on fragile footing with regard to supply and maintenance.
The Commission entertained three scenarios:
- Scenario 1: End U.S. Participation in the ISS at the end of 2015.
- Scenario 2: Continue ISS Operations at the Present Level to 2020.
- Scenario 3: Enrich the ISS Program and Extend through 2020.
Scenario 1 was rejected. Scenario 2 keeps the ISS alive for use by the international community, but does “not allow the ISS to achieve its full potential as a National Laboratory or as a technology testbed. The majority of the funding is devoted to sustaining basic operations and providing transportation”.
With Scenario 3, the Commission provides discussion and insight into the importance of additional funding associated with the extension of the ISS mission. Two quotes illustrate this:
The National Research Council Space Studies Board has recently initiated a decadal survey of life and microgravity science that will identify key scientific issues and strategies for addressing them. This is the first decadal survey in this area, and it will bring the most modern scientific understanding to bear on what questions may be answered in the decade through 2020
The Committee believes that the Space Station can be a valuable testbed for the life support, environmental, and advanced propulsion technologies, among others, that will be needed to send humans on missions farther into space. It also has the potential to help develop operational techniques important to exploration.
Having examined two active human space flight programs, the Committee waded into the thorny world of the Briar Patch.
4.3 The Constellation Program
The Constellation Program consists of the Orion crew exploration vehicle (CEV), the Ares I crew launch rocket, the Ares V cargo launch rocket and the Altair Lunar surface access module (LSAM).
The Orion was originally designed to field a crew of six for missions as long as six months, with a service module and launch abort system (LAS). Due to reduced capabilities anticipated for the Ares I, the Orion is facing continuing design changes, reducing its capacity to four crew, and requiring other design compromises. The report concludes that:
When compared to historical programs, the most likely delay to the Orion availability approaches 18 months. Additional critical paths exist through ground test and flight test.
At this point, the report examines the historical record and the mismatch between program contend and funding (see Figure 4.3.2-1. Constellation Program Funding Profiles. Source: NASA, p. 59):
- ESAS original funding was scheduled to rise from $4.5 Billion in 2009 to $10.0 Billion in 2017.
- Fiscal Year 2009 budget was to rise from $3.3 Billion to $8.3 Billion by 2017.
- Fiscal Year 2010 budget rises from $2.9 Billion to $6.8 Billion in 2017.
These cuts have severely hampered the Constellation Program. This is a 45% reduction in budget in 2009 from the ESAS budget voted by Congress to the actual appropriated amount, and a 32% reduction by 2017. Congress and the previous administration are to blame for failing to fulfill their promises (what’s new?), and NASA is to blame for believing the unfunded promises of the politicians. Plenty of rope to hang everybody.
The next target of the Commission is the Ares V (about which much will be said later). To quote the report, “The Ares V, still in conceptual design, promises to be an extremely capable rocket—able to lift 160 metric tons of cargo into low-Earth orbit”. Now this classification of Ares V is interesting, because as we have previously noted, the Program of Record (PoR – Constellation; see CxP 70000 Constellation Architecture Requirements Document (CARD) Rev 3 Change 001, March 2009), requires that 71.1 mt of cargo be sent to the Moon (“the lander must mass no more than 45,000kg, Orion mass 20,185kg, ASE mass 890kg and there is 5,000kg of Manager’s Margin included for safety. That’s a grand total of 71,075kg or 71.1mT of total spacecraft mass being pushed thru TLI”). This is one of the “Misses” that the Commission makes. Instead of scoring proposed architectures by the requirements of the program proposed to justify the architecture, scoring seems to have been done against an architecture, absent the program. One wonders why Ares V needs to be so big.
Altair is by-passed in this chapter with a reference back to chapter 3.0. Subsequent to the release of the Commission’s report, development of Altair has been suspended, pending decisions by the current administration.
Finally, the Committee deals gingerly with Ares I:
The Ares I is currently dealing with technical problems of a character not remarkable in the design of a complex system – problems that should be resolvable with commensurate cost and schedule impacts. Its ultimate utility is diminished by schedule delays, which cause a mismatch with the programs it is intended to serve.
We are left, therefore, with hits and misses so far. Hits include the Goal. Also, the value of the Shuttle for up-mass and down-mass in the support of the ISS. Furthermore, the potential value of the ISS for scientific research, international cooperation, space based construction and maintenance, technological testing and human factor research.
Misses focus around the arbitrary choice of hardware capability without regard to Goal or mission.
Part 4 next.