USDV Industry Day Questions and Answers.pdf

United States Deorbit Vehicle Industry Day Questions and Answers

1. Question: Does NASA expect the U.S. Deorbit Vehicle (USDV) to remain attached to International

Space Station (ISS) throughout the deorbit process?

Answer: Yes. The Final Deorbit Burn will end with a Vacuum Perigee of 50 km or lower, well below the altitude where the USDV could safely undock.

2. Question: In the Launch Vehicle Certification and Procurement section of the Request for Information (RFI), was it NASA’s intent to ask, “If the launch vehicle was [NOT] included with the USDV contract, what is industry’s input into the most effective method of handling the launch service procurement?”

Answer: No. The question is correct as written in the RFI.

3. Question: Did NASA consider active orbit maintenance at a lower altitude rather than passive orbit life at 40,000 km for keeping ISS on orbit?

Answer: Yes, NASA did consider active orbit maintenance at lower altitude. The vehicle altitude limit is 460km which requires continued delivery of propellant resources to maintain and thus requires active control of the ISS. At the end of ISS program, NASA’s intent is to reduce operational costs. NASA does not want to have active oversight of the vehicle due to the required workforce and resources to actively maintain ISS at any altitude beyond ISS End of Life.

4. Question: Can you share your trajectory calculations, assumptions, and flight performance reserve that go into 57m/s and assumptions on attitude control dead bands?

Answer: Yes. The ISS Deorbit Concept of Operations, located in the 80JSC022ISSDeorbit Technical Library Attachments list, includes the overall deorbit plan, including the breakdown of the 57 m/s delta-V to accomplish the target reentry. The attitude control performance requirements are included in SSP 51101, United States Deorbit Vehicle Systems Requirements Document. Information is also outlined in the Industry day Charts, Slide 22 titled “USDV Requirements Overview”.

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