Status Report

Report on Top-Level Assessment of Use of Apollo Systems for ISS CRV (part 2)

By SpaceRef Editor
April 28, 2004
Filed under , ,

Part 1 (text) | 2 (tables)

Table 1

A Comparison of Apollo-Derived Crew Rescue and Crew Transport Vehicles

Design Apollo outer mold line

15 psi cabin for ISS match

Strap on retro rocket

No service module

No cryos, no fuel cell, batteries

Water bottles and air bottles

Land recovery

Simplest adaptation of CM
Improved CRV plus SM

More volume in CM by:

– transferring cooling to radiators

– Transfer air bottles to SM

Apollo Launch Escape System

Land Recovery

Added delta V

Added systems and complexity
Transport to ISS Shuttle up, CRV down EELVE and SM up,

SM and CTV down
Operations CRV only has 18 miles X-range

Therefore must wait in space to better pick a few landing sites

Large recovery infrastructure
At about 50,000 lb. EELV payload limit; SM probably smaller than Apollo SM, but delta-V 3000 – 5000 fps means fewer landing sites
Schedule 4 to 6 years after contract with optimum annual budget profile
5 to 7 years after contract with optimum annual budget profile
Cost Judgment ** Development and manufacturing cost could be less than winged vehicle due to less complexity.

Ground infrastructure likely more costly than for winged vehicle
Development and manufacturing cost could be less than winged vehicle due to less complexity, CTV version would reduce ground infrastructure requirements
Reliability and Availability Major ground test program required because so few in operation and so few flights
A few more flights per year than CRV, but still a challenge to get and prove reliability

** assumes no Apollo hardware utilized.

Table 2
Assessment of Apollo-Derived CRV/CTV against Level 1 Requirements

Mission Needs Statement Apollo-based CRV
CTV Implications Notes
Support the US ISS requirements for CRV, CTV, and cargo The Crew Return requirement can be provided for at least 4 crewmembers in a single CM-derived CRV The Crew Transport can be provided with the Apollo-based CM with a Service Module. Cargo will be limited to the volume provided in the SM. It could not provide the heavy cargo delivery requirement
1. Rescue capability for 4 crew by 2010, including medevac The CMCRV, with no Service Module, except for the de-orbit propulsion module, would be capable of rescue for 4 crew, and possibly up to 7 crew, if additional landing sites were added. A water landing recovery is also possible as a minimum system, based on the 1 mile landing accuracy demonstrated by Apollo. N/A Prior studies have shown that the CM could carry 6 crew members (volume). More detailed studies would be required to determine if 6 or 7 crew members could be accommodated with consumables, power, RCS propellant, cooling water, and new internal equipment in a rearranged interior.
2. Rescue capability for deconditioned, ill, injured to definitive care with or without suits. The CMCRV would have a cross-range of less than 20 miles thus requiring multiple landing sites and/or sufficient on-orbit time for site selection. The latter trade may be traded for the 24 hour requirement. The rescue of injured or ill crew appears to drive capability to land recovery. None For both this requirement and Req. #1, a scaled-up CM (5-7%) would provide volume for on-orbit time and numbers of landing sites.
3. Rapid separation from the ISS Thrusters on the de-orbit module (e.g. similar to R4D’s) can translate CRV rapidly from ISS following commanded unlatching or explosive bolt separation from the docking adapter. Compatible sub-systems may be used for CTV configuration with more capable Service Module. The 3-year storage on orbit of Apollo hypergolic propellants must be confirmed.
4. Crew rescue 99%/95% with rescue capability better than Soyuz The conceptual nature of this assessment precluded numerical analyses of any of the critical metrics including safety. Some factors contributing to safety favorable to the Apollo-derived CRV over all new system are: proven success of Apollo concept; well-understood environment; massive aerothermal database. N/A For any system, this metric will have to be predicted, because of the small number of test flights and probable infrequent use on ISS. The Soyuz has approximately 100 entries and has demonstrated high reliability.
5. CTV capability by 2012 N/A An Apollo-based CRV/CTV with a Service Module and land recovery can be fielded by 2012 assuming a timely start and EELV human qualification is not the long pole. Low risk integration with EELV (no lifting surfaces)
6. Loss of crew < 1/400 and lower risk than STS Not assessed. Factors influencing safety for CMCRV include proven Apollo Launch Escape System and abort modes, lower parts count, proven concept. It should also be possible to sustain comfortable weight margin. It was judged that an Apollo- derived system would have Lower F (POC) than STS, based on these factors. For any system , this metric will have to be predicted by analysis, because of the small number of test flights and low flight rate to ISS.
7. Minimum life-cycle costs Not analyzed. Factors contributing to LCC favorable for Apollo-derived system over all- new system are extensive operational experience; proven concept; simplicity; potential for high degree of reusability for expensive crew module. Same as for CRV There are obvious trades between number of landing sites, on-orbit capability, water/land recovery, number of crew (4-7)
8. ISS interface requirements No known issues. The berthing adapter interface will be designed to ISS specifications. Same as for CRV Trickle charge for CRV batteries are required and wiring interfaces for ISS monitoring, etc.
9.0 Preparation for launch compared with Space Shuttle N/A It seems highly likely that less time will be required to prepare a simple Apollo-derived CRV than for the STS. Weather constraints are estimated to be similar to those for STS. Launch in bad weather not judged to be a wise action for any launch vehicle. EELV launch vehicle constraints would probably dominate here (e.g. wind limit to clear tower).
10.0 Increased on-orbit maneuverability than Space Shuttle N/A The Service Module can provide significant delta-V this has to be traded of with crew size, on-orbit time, landing sites, and constrained by EELV payload to ISS. Orbital plane capability charge offers mission flexibility and some benefit in landing site selection. It is an important trade factor for any CTV.

Operations Concept Apollo-based CRV Assessment CTV Implications Notes
1.0 Initially launch on an EELV The Apollo-derived CRV is carried to ISS in the Shuttle payload bay and berthed using the ISS remote manipulator system. The berthing adapter is pre- positioned. The Simple CRV would not have an independent rendezvous and docking capability The CTV with Service Module would be launched on an EELV and have rendezvous and docking capability. Docking capability may be needed also to cover contingency cases. If so, a probe and drogue probably are required at the CM docking interface.
2.0 Operate through 2020 No limiting factors known No limiting factors known
3.0 Commonality The CRV and CTV/SM could be developed serially or in parallel, and would have a very high degree of commonality. Operational experience with systems with CTV could be incorporated in the CRV in Block upgrades. Commonality between CRV and CTV appears to be achievable assuming addition of an SM
4.0 Cargo delivery N/A Cargo capability within the CM-derived CRV can support smaller cargo requirements. The CTV also has a Service Module with cargo carry volume and weight a trade factor with delta-V propulsion and consumables for crew, if aboard. Offsetting factors in CMCRV to carry larger number of crew are packaging challenges vs. smaller size of modern avionics/displays, and use of modern lighter-weight materials. CTV with the Service Module affords significantly large design trade space.

SpaceRef staff editor.