Quote from: AegeanBlue on 02/23/2018 06:13 PMI am surprised that this article has not been shared yet:http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/Per the article they do not consider Falcon Heavy because they doubt that it will be certified for Class A missions at launch time.I do not see the words 'Class A' in the article, and am I missing this, or has it changed.
I am surprised that this article has not been shared yet:http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/Per the article they do not consider Falcon Heavy because they doubt that it will be certified for Class A missions at launch time.
Quote from: Demidrol on 02/14/2018 05:40 PMQuotePappalardo said the mission is continuing to study the use of Delta 4 Heavy and Falcon Heavy as alternatives, but those would require the use of gravity assists that increase the mission’s flight time. The use of the Atlas 5 has been “closed off,” he said.http://spacenews.com/europa-mission-planning-for-possible-budget-cuts-in-2017/Article was dated August 17, 2016. A door closed 1.5 years ago or more could be re-opened?Also, this article quote doesn't appear to preclude use of Vulcan/Centaur.
QuotePappalardo said the mission is continuing to study the use of Delta 4 Heavy and Falcon Heavy as alternatives, but those would require the use of gravity assists that increase the mission’s flight time. The use of the Atlas 5 has been “closed off,” he said.http://spacenews.com/europa-mission-planning-for-possible-budget-cuts-in-2017/
Pappalardo said the mission is continuing to study the use of Delta 4 Heavy and Falcon Heavy as alternatives, but those would require the use of gravity assists that increase the mission’s flight time. The use of the Atlas 5 has been “closed off,” he said.
NASA has studied launching Europa Clipper on both SLS and on the most powerful variant of the United Launch Alliance Atlas 5. SLS offers the ability to fly a fast, direct route to Jupiter, with the spacecraft arriving at the planet less than three years after launch. The Atlas 5 would take more than six years to get Europa Clipper to Jupiter, and require flybys of both Venus and Earth to do so.
Isn’t there some odd situation where Europa Clipper is classed as a class b mission at the moment?
The independent review also raised questions about the risk classification of the mission. WFIRST is considered a “Class B” risk mission by NASA, which means it is high priority but only medium to high cost and with a medium mission lifetime. That is less stringent than the Class A assignments usually given to “strategically important missions with comparable levels of investment and risks,” Zurbuchen wrote.The review, the memo noted, suggested NASA add more engineering development and spare hardware, as well as additional analysis, “to provide a more robust program” than its existing Class B risk classification.
Quote from: Star One on 02/23/2018 08:36 PMIsn’t there some odd situation where Europa Clipper is classed as a class b mission at the moment?You're thinking of the controversial Class B designation for WFIRST:QuoteThe independent review also raised questions about the risk classification of the mission. WFIRST is considered a “Class B” risk mission by NASA, which means it is high priority but only medium to high cost and with a medium mission lifetime. That is less stringent than the Class A assignments usually given to “strategically important missions with comparable levels of investment and risks,” Zurbuchen wrote.The review, the memo noted, suggested NASA add more engineering development and spare hardware, as well as additional analysis, “to provide a more robust program” than its existing Class B risk classification.http://spacenews.com/nasa-seeks-cost-cutting-changes-in-design-of-wfirst-mission/
It would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.In the end, I think Clipper rides another vehicle.
Quote from: Don2 on 02/24/2018 07:40 PMIt would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.In the end, I think Clipper rides another vehicle. The sooner that decision is made the better.
One wonders how SLS is supposed to be certified by then.
From another topic:MATTBLACK:Yes - things would certainly look good for lunar missions, doing 'distributed launch' of the spacecraft and the Earth Departure Stage (EDS). A Falcon 9 could place a 20 ton Lander or Command Module type vehicle into orbit first. A Falcon Heavy places it's upper stage as an EDS into orbit next, where it's only payload is propellant (65-70 tons?) and a docking mechanism. The spacecraft docks with this and the EDS burns for TLI.Why not use the scheme for Europa Clipper?Can Atlas 401/F9 and F9H provide direct flight to Jupiter?
In a presentation at a meeting of the Committee on Astrobiology and Planetary Science of the National Academies March 28, Kevin Hand of the Jet Propulsion Laboratory said that feedback from a mission concept review for the proposed lander last June led to changes in the design to reduce its cost.“The technology and science were well received. The marching orders that we got out of that review were to see if we could simplify the architecture to reduce complexity and cost,” he said. While there’s been little discussion of the lander’s cost, Hand said there was a “desire” to reduce its cost to below $3 billion.The concept for the mission presented at that review involved the launch of the lander on a Space Launch System rocket no earlier than late 2025. The spacecraft would enter orbit around Jupiter in 2030 with a landing on Europa to follow no earlier than December 2031. The battery-powered lander would operate on the surface for at least 20 days, relying on a communications relay spacecraft in orbit to return data to Earth.
Twenty days on the surface doesn’t seem all that much for the time and money invested.
Another factor that enables the change in design, he said, is a shift in the science requirements for the lander. A report by a science definition team last year had included, as one of the mission’s priorities, the ability of the lander’s instruments to directly detect any life that might exist in the moon’s icy surface.“That’s a very high bar,” Hand said. “That bar runs the risk of setting expectations too high, perhaps, and also potentially cannibalizing some of the other science that the community sees as very valuable.”Instead, the mission team looked at what the “sweet spot” for science from the lander mission might be. Hand said that looking for biosignatures of past or present life would simplify the science requirements for the mission, including reducing the amount of data needed to be transmitted back to Earth.
So is the main part of the redesign to ditch the orbiting relay setup, leaving basically the descent module and the lander?
Quote from: redliox on 03/29/2018 10:34 PMSo is the main part of the redesign to ditch the orbiting relay setup, leaving basically the descent module and the lander?The briefing was at one of our meetings that just ended today. The Europa lander is going through a lot of redesign. The big change was to get rid of the orbiter, but they've also changed the science focus a lot. The goal is to both get the cost down and to broaden the mission because the focus on finding life was considered too narrow. There are some interesting animations as well. The lack of data about the surface makes landing really challenging, so one of their goals is to develop a very smart landing system that can choose the best landing site in real time.
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