[X] My Assistant

[RNeuhaus]

This topic is for posts concerning to any preparation of Phoenix Lander Mission to Mars programmed to launch on August 2007 (less than 2 years... but the time will fly)

http://marsprogram.jpl.nasa.gov/missions/future/phoenix.html

Overview

The Phoenix mission is the first chosen for NASA's Scout program, an initiative for smaller, lower-cost, competed spacecraft. Named for the resilient mythological bird, Phoenix uses a lander that was intended for use by 2001's Mars Surveyor lander prior to its cancellation. It also carries a complex suite of instruments that are improved variations of those that flew on the lost Mars Polar Lander.

Canada Will Land Instrument On Mars To Study Weather

http://www.spacedaily.com/news/mars-future-05t.html

Rodolfo

[Bob Shaw]

Did MPL fly the same radar altimeter as Phoenix will? For a variety of reasons (many of which I disagree with, but that horse has been beaten into its constituent atoms on other threads), a lot of basic avionics like RAs & inertial reference units seem to get re-invented for new missions.

I think, given the problems with MPL's descent, that a new radar might have been a prudent move!


Bob Shaw

[nprev]

Point taken... , but what I was trying to say is that given the fact we've successfully landed on Mars five times, why not fly a proven instrument? For Phoenix, I'd say that the MER RA would have been ideal...though the project timeline may not have made that evident in time for CDR.

Understand the issues of technological advancement, obsolescence, vanishing vendors, etc., but I suggest that for Mars landings it would be wise to procure something like a 10-year suite of critical flight avionics that have been 'combat tested' for use on all missions during that period. Kind of a larger infrastructure investment than a given project could foot on its own, but IMHO a less risky approach.

"Better is the enemy of good"...especially when talking about equipment designed to perform similar functions used in high-risk endevours, like UMSF!

[djellison]

The requirements for the MER Radar and Phoneix Radar would be a little different I would have thought - the Phoenix radar would be required to do a bit more than just altitude.

Doug

[Jim from NSF.com]

Point taken... , but what I was trying to say is that given the fact we've successfully landed on Mars five times, why not fly a proven instrument? For Phoenix, I'd say that the MER RA would have been ideal...though the project timeline may not have made that evident in time for CDR.

Understand the issues of technological advancement, obsolescence, vanishing vendors, etc., but I suggest that for Mars landings it would be wise to procure something like a 10-year suite of critical flight avionics that have been 'combat tested' for use on all missions during that period. Kind of a larger infrastructure investment than a given project could foot on its own, but IMHO a less risky approach.

Phoenix is different from MER which is different than MSL. How many missions does this 10 years cover? And who is building the landers, JPL, LM, or someone else?
Like you said, "issues of technological advancement, obsolescence, vanishing vendors" this would be th problem.

[stevesliva]

Remember that hundreds of millions of dollars have already been spent on the project and to cancel it would waste everything. The DAWN project had a similar review and was put on hold for months but was eventually reinstated.

Sunk cost... the decision shouldn't be to justify past expenditure, but to justify additional future expenditure. You stop and ask, given what it will cost me to finish this hardware and complete the mission, is it worth it? Unless you have grossly awful hardware like the composite LH2 tank on the VentureStar--when you actually are throwing a lot away and starting from scratch--the answer is usually yes. But, then again, the superconducting supercollider proved that sunk construction costs don't commit the government to finishing their projects!

(yes, oversimplified discussion of VentureStar's woes, but the point is that sunk costs don't guarantee that problem programs get the green light to spend more, especially given political climate changes.)

[nprev]

Phoenix is different from MER which is different than MSL. How many missions does this 10 years cover? And who is building the landers, JPL, LM, or someone else?

Oh, no argument that these missions are quite different, and the "NIH" syndrome would be a significant obstacle to overcome...

Using radar altimeters as an example, this is a mature technology designed for a specific, common, flight-critical function...why continuously re-invent it? If there was a NASA directorate focused on developing common avionics boxes, then they might produce a new "standard RA RT" every ten years or so based on a demand of, for example, four lunar and/or Martian landers over that period. The SRA RT would have programmable vehicle MIL-STD-1553 & let's say RS-422 serial data interfaces (as well as available discrete outputs for event triggering) & an adaptable power supply (let's say between 10-32 VDC). The installation variables would be antenna type & placement as well as antenna cabling.

This essentially makes any standard box (in addition to RAs, I'm thinking of IRUs, comm transceivers, Sun/star sensors, etc.) a constraint for a given mission, since designers would have to figure out how best to install it, evaluate mass & volume impacts, etc. However, this also removes the burden of designing & building (or arduously selecting) their own, which may drive down costs & decrease developmental time (esp. if the boxes were provided gratis by NASA as government-furnished equipment). There even may be some pressure to use up the stock, which might translate into more approved missions...

[mcaplinger]

Using radar altimeters as an example, this is a mature technology designed for a specific, common, flight-critical function...why continuously re-invent it?

The MPL/PHX radar is a multibeam Fourier doppler radar that can measure velocity. The MER radar didn't need to do that, and couldn't. So there are legitimate engineering reasons to develop new designs that I don't think you are appreciating.

There's plenty of standardization for box-level avionics: the LN-200 IMU and the Small Deep Space Transponder come to mind.

http://marstech.jpl.nasa.gov/publications/...C-1188-2005.pdf has some background on the MPL radar, and a proposed radar design for MSL.

[nprev]

I stand corrected (& thanks for the clarification! ). I was unaware of the standardization efforts you described; hopefully the trend will expand as appropriate & practical.

[edstrick]

"...The MPL/PHX radar is a multibeam Fourier doppler radar that can measure velocity. ...

I would have thought that the Mars 2001 lander that was "Transformered" into Phoenix had a perfectly decent radar, probably derived from the Polar Lander technology. It's not as though this was the hottest new technology. Viking and the lunar Surveyors did it. Granted, they'd be heavy and made of parts no longer available, but this seems more than a bit strange that's it's a bit $ impact. I'd like to know "THE REST OF THE STORY...."

[Jim from NSF.com]

Using radar altimeters as an example, this is a mature technology designed for a specific, common, flight-critical function...why continuously re-invent it? If there was a NASA directorate focused on developing common avionics boxes, then they might produce a new "standard RA RT" every ten years or so based on a demand of, for example, four lunar and/or Martian landers over that period. The SRA RT would have programmable vehicle MIL-STD-1553 & let's say RS-422 serial data interfaces (as well as available discrete outputs for event triggering) & an adaptable power supply (let's say between 10-32 VDC). The installation variables would be antenna type & placement as well as antenna cabling.

This essentially makes any standard box (in addition to RAs, I'm thinking of IRUs, comm transceivers, Sun/star sensors, etc.) a constraint for a given mission, since designers would have to figure out how best to install it, evaluate mass & volume impacts, etc. However, this also removes the burden of designing & building (or arduously selecting) their own, which may drive down costs & decrease developmental time (esp. if the boxes were provided gratis by NASA as government-furnished equipment). There even may be some pressure to use up the stock, which might translate into more approved missions...

NASA doesn't fly enough missions or "common boxes" to justify this. Also why should NASA develop the boxes? That is for industry to do (market driven economy)

The boxes referenced (INU, SDST) aren't part of a focused "standardization" effort. Just some some onezes and twoezes that have become COTS.

[Steve G]

NASA doesn't fly enough missions or "common boxes" to justify this. Also why should NASA develop the boxes? That is for industry to do (market driven economy)

The boxes referenced (INU, SDST) aren't part of a focused "standardization" effort. Just some some onezes and twoezes that have become COTS.

Any chance of Phoenix being woken up the following spring after a year long hibernation? Once the solar panels begin to generate power, what would it take to thaw the thing out and reboot the electronics? No one ever thought the Mer rovers would be working into their forth year, so why not ask the preposterous?

[Decepticon]

I was wondering about that to. Can the lander be put into Hibernation?

[Rakhir]

Some discussions about the Phoenix hibernation are available in the same thread
Here
Here
And here

[Jim from NSF.com]

They saw the heatshield up close....but not the chute and backshell

And I still think the opportunity for a self portrait in the reflective insulation on the heatshield was a tragic miss
Doug

This would have all burned out

[djellison]

http://pancam.astro.cornell.edu/pancam_ins...heatshield.html
http://pancam.astro.cornell.edu/pancam_ins...heatshield.html

Swathes of unburnt reflective insulation from inside the heatshield - some reflecting the sun, some the sky, some the ground.

Doug