I'm happy to report that we now have pictures from the spacecraft, downlinked through Mars Odyssey. The pictures are what we refer to as "postcards." They're black and white pictures meant primarily to tell whether our deployments successfully occurred. From what we can see, the solar arrays have successfully deployed as well as the Surface Stereo Imager and Biobarrier. The pictures also show a beautiful Martian landscape of which I personally can't wait to see color panoramas in the days to come. Even in black and white, the pictures gave everyone in the room cause to break into cheers and gaze in awe and amazement at a landscape that suggests we simply dropped in on another peaceful day on Mars. Needless to say, these pictures will be shown at the press conference that will take place at 9:00 pm (PST) tonight.
This will conclude the Approach and EDL blog. This has been a wonderful opportunity and experience. On behalf of my fellow bloggers Leslie Tamppari and Deborah Bass, and the whole Phoenix team, I'd like to thank everyone for all their comments and wishes. The excitement that everyone has for what we do at JPL is part of what makes our jobs so exciting. I apologize to anyone whose questions I couldn't get to. Please be sure to continue to watch the websites listed at the bottom of the blog, where you'll be able to find more images and updates on the mission as we continue our exploration of the arctic plains of Mars for the next several months.
Thanks again to all!
Now that things have settled down a bit, I'd like to answer a few more questions.
On reader asked a question about the temperature of the ground. At night we expect this temperature to be as low as 196 degrees Kelvin (-106 degrees Fahrenheit) and as much as 256 degrees Kelvin (1.13 degrees Fahrenheit) during the day.
Another reader was asking whether it's normal that we only had communication with Odyssey until one minute after touchdown. This is by design. We turn off our radio at one minute after touchdown. This is in order to conserve our energy. At this point, we haven't yet confirmed that our solar arrays are deployed. Therefore we only keep the spacecraft awake long enough to do those deployments, after which it goes to sleep for a while until the next pass by Mars Odyssey and Mars Reconnaissance Orbiter.
This brings me to another question regarding whether Phoenix can communicate directly to Earth. The answer to this question is no. Phoenix communicates to the Mars Odyssey and Mars Reconnaissance Orbiter spacecraft which then communicate with Earth. Their orbits, however, allow at least two passes per Sol (a Martian day). We use one for uplink and the other for downlink. Although an antenna at Green Bank, West Virginia listened for our UHF signal during EDL, it can only pick up a faint carrier signal. It can't discern any data. Consequently, we communicate with Phoenix only through Mars Odyssey and the Mars Reconnaissance orbiters.
Another reader asks what platform we use on our computers here in Mission Control. The computers that display data coming from the Deep Space Network use custom displays operating on Unix machines.
Of course I realize that everyone reading is just as anxious to see pictures from the surface of Mars as I am. Odyssey will begin its first pass over Phoenix at about 6:43 pm (PST). We may have pictures as soon as 40 minutes from then. If we have them, they'll be posted to the internet as fast as possible, and also be shown at the 9:00 pm (PST) press conference.
Phoenix is now on the surface of Mars, much to the joy of everyone here in Mission Control. As icing on the cake, we've found that the lander is tilted only one quarter of a degree, which means we've landed nearly perfectly level. The next step for Phoenix is surface initialization during which the solar arrays, Surface Stereo Imager (SSI), Biobarrier (which has been protecting the robotic arm from contamination since it was sterilized on Earth) and meteorological mast will deploy. We should have data regarding the status of these deployments when Odyssey makes its first pass in less than two hours. Engineers in Mission Control are saying that our actual landing went far smoother than any simulation or test that was ever done. Stay tuned.
Touchdown detected!! We're on the surface of Mars and there is celebration in Mission Control!!
Parachute deploy detected! Heat shield deploy detected! Radar ground lock detected!
Odyssey has maintained a signal from Phoenix through the period of peak heating when we might have experienced a loss of communications due to plasma blackout.
Phoenix has now entered the atmosphere. We expect possible plasma blackout in about a minute. Phoenix is less than three minutes to parachute deploy and less than seven minutes to touchdown.
We have now verified a successful cruise stage separation and turn to entry. The Phoenix UHF signal is also being picked up by Mars Odyssey. We're now less than six minutes from entry, at which point events will happen in rapid succession. Less than a minute after entry, Phoenix will begin heating to the point of plasma blackout due to the friction created by the atmosphere, during which we may lose communication briefly. Phoenix will then come out of plasma blackout about two minutes later. Over the four minutes following that, Phoenix will deploy its parachute, heat shield, lander legs, and then hopefully come to a soft landing on Mars.
The Mission Manager, Joe Guinn, has just announced that we should all be at our stations in preparation to bid farewell to our cruise stage, which has provided us an excellent trip to Mars. Cruise stage separation is in eight minutes.
We've now confirmed completion of the successful pressurization of the descent engines. This is a critical event that is now behind us. We're expecting cruise stage separation in less than twenty minutes.
There has been a request for clarification regarding the EDL timeline. The timeline posted below is what we refer to as the "Earth Receive Time." This is the time when we get the signal here in Mission Control. Since it takes fifteen minutes for a signal to get from Mars to Earth, all the EDL events occur about fifteen minutes prior to the data we received confirming that these events happened. We've also just received confirmation that Odyssey has completed a slew in preparation for relay operations during EDL. Also, it was just announced that the peanuts are being opened and distributed here in Mission Control. This is a JPL tradition that goes back to the Ranger missions to the moon in the sixties.
For those of you watching NASA TV, you're seeing periodic shots of Mission Control in between and during interviews. From where I sit, and what your probably can't see, are the rooms surrounding Mission Control, which are also full of people. Two of the four walls are glass windows, opening to to the "dark room" from which Gay Yee Hill is broadcasting on NASA TV, as well as another conference room. I can also see a viewing gallery above the "dark room" which is also full of people. Everyone is excited and you can feel a nervous tension building. Some folks in Mission Control are even talking via cell phones through the glass as they wish each other luck.
It's great to see so many people following along in the comments. We are currently receiving real-time data from the spacecraft via the Deep Space Network. In fact, we had near continuous coverage for the last couple weeks in order to keep a careful eye on the spacecraft status. Some of you may notice from the live shot on NASA TV a green and black chart on the wall. This chart shows our Doppler shift as a result of the increase in speed of our spacecraft due to the Mars "gravity well." As get closer and closer to Mars, we pick up speed due to gravity. We enter the atmosphere at over 12,000 miles per hour, relative to Mars. We are now about an hour from EDL.
We've just completed the 90-minute (from EDL) poll, verifying that the Mars Odyssey orbiter, Mars Reconaissance Orbiter, and Mars Express are "go" for EDL communications support. While Mars Odyssey relays data back to Earth during EDL, Mars Reconaissance Orbiter will play back data later.
For those of you who'd like to follow along on NASA TV, live shots are now being shown periodically from the MSA. There will be some interviews as well. We just completed voice checks as we make our way through the EDL procedure. If you notice folks referring to a thick book at their desks, this is the Approach and EDL procedure, several hundred pages long, that lists each step executed throughout our approach to and landing on Mars. This procedure, in fact, starts several weeks back. Also, the Project Manager just stopped by and wanted me to say hi to everyone reading on the web.
We are now two hours out from EDL. The team has assembled in Mission Control, from where I'm now blogging. Everyone is excited and nervous as the spacecraft nears Mars. All the final uploads have been made and we are now along for the ride as five years of hard work reaches its climax. The project manager is making his way through Mission Control wishing everyone luck as we ready ourselves for EDL. Stay tuned for updates.
Welcome back to the Phoenix landing blog, being written from JPL in Pasadena, CA, where today engineers are anxiously awaiting the arrival of the Phoenix spacecraft at Mars. Less than seven hours from now, Phoenix will enter the Martian atmosphere, heading towards its landing site in the northern arctic plains of Mars. It was decided yesterday afternoon that no trajectory correction maneuver (TCM) would be needed last night, but left open the option for another TCM eight hours before landing. Likewise, it was again decided this morning that the spacecraft trajectory is close enough that no correction is needed today either. Sleeping bags and cots scattered throughout offices and cubicles hint at the long night team members have had making final preparations for EDL this afternoon. The final EDL parameters were uploaded to the spacecraft this morning, drawing to a close the task of preparing the spacecraft for landing. Everything from this point out will happen autonomously.
In addition, the final EDL timeline was issued just this morning. The table below shows the time at which important events will be taking place in the course of EDL.
|Cruise Stage Separation
|Nominal Plasma Black out start
|Nominal Plasma Black out end
|Nominal Parachute Deployment
|Nominal Heatshield Deployment
|Nominal Lander Leg Deployment
|Nominal Lander Separation
|Nominal Touch Down
A number of questions have come up in response to the blog regarding the search for life on Mars. To be sure, Phoenix isn’t looking for life itself. Instead, Phoenix will evaluate whether life could survive here, or the habitability of Mars, by looking at the building blocks of life: water and any organics which may be located in the soil. Depending on what Phoenix finds, future missions will follow Phoenix in response to these discoveries; much as Phoenix followed the Mars Odyssey in response to its discovery of subsurface water ice in the Northern plains.
In addition, we’ve taken numerous precautions to avoid bringing organic material with us to Mars. The spacecraft is assembled in a clean room and kept under such stringent cleanliness requirements all the way through launch. In addition, the Phoenix robotic arm is kept within what we call the “biobarrier.” This is a protective bag that encases the robotic arm, which is the tool that will actually do the digging on Mars and comes in direct contact with any samples we analyze. After being sterilized in an autoclave, the robotic arm was placed within the biobarrier, which will only be opened once we’re safely on the surface. The Phoenix science team has gone to great lengths to ensure that all the science we do on the surface of Mars will be valid.
As you can imagine the excitement is building in anticipation of a big day here at JPL. News vans are filling the parking lot, and special guests will be arriving before long to view the landing. As you can imagine, the Phoenix team is excited but nervous, and everyone is finding their own way to burn that energy in the last few hours of waiting that’s left before we take our seats in Mission Control around 2:00 pm (PST).
Check back to this page often, as updates will be posted here throughout the day.
Phoenix Configuration and Information Management Engineer
To learn more about the spacecraft and the mission, check out the following sites:
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