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ULA ACES & ESPA ring outer planet probe 2.0

December 16, 2017

Takeaways from past ULA ACES ESPA ring outer planets science missions posts

(A) there is no docked spacecraft, the ACES is the science probe.

(B)The NASA launch services contract pays for a portion of the ACES as upper stage and this portion does not come under the AO mission cost caps.

(C) The ACES is a certified launch vehicle that should reflect on TRL of the proposed science mission, a certified lunch vehicle should receive the highest TRL form the AO selection committee for an ACES science probe

(D) The ACES IVF controller and ACES avionics are meant to last for 20 years in deep space and are partnered with the flight computer and data systems for science, This means the system must be able to do station keeping, instrument pointing and small TCM with ballistic moon flybys. This systems science instruments and Xenon station keeping requires RTG so that end of mission does not occur after IVF system exhaustion. The OPAG Ice Giant study report states that deep space avionics and comnav are $300 million per flight and the 13 science instruments are  $400 Million, there is no real way to reduce this cost for reliability

(E) the ESPA rings are about 5.4 meters < to match that of the ACES both aft and forward bulkhead some of the most foreword ESPA rings can be smaller(landers)

(F)The aft ESPA ring has electrical connections to the IVF controller and deploys a solar array that powers a SEP engine, RTG only powers science and avionics & comnav. Keep this solar array for Saturn missions jettison for Uranus Neptune.

(G) The ACES propellent  intertank regions can carry atmosphere probes

(H) ACES that does Venus Earth Earth trajectory to the outer planets benefit from a Methane LH2 gell to lower boil off

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Can some of the ACES R&D come under the mission cap of Discovery 2019? Or could NASA infuse future Cryogenic technologies to infuse as government furnished equipment?

18-Mustafi  (TOPS)

NEXT SEP Ion engine has already been approved for Infusion at no cost to the AO mission costing cap Unlike TOPS and We would propose that we need to model a 7-ton ACES dry mass at Neptune how much cryogenic Xenon Oxygen and Hydrogen would get the job done.







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