Two Sunday Landing Attempts Set for Uncrewed Boeing Starliner
Boeing & NASA held a status update call with media at 2PM Eastern time on Saturday December 21, 2019. The Starliner spacecraft is in a circular orbit 155 miles above the Earth. Mission control teams in Houston have been pursuing two primary objectives: to maintain spacecraft integrity and orbital trajectory for two landing opportunities on Sunday, Dec. 22., and to complete as many mission tests as possible.
Teams from NASA, Boeing, and the U.S. Army have been working together for the landing.
NASA Administrator Jim Bridenstine: "We have a healthy spacecraft. NASA and Boeing have been working hand-in-glove to achieve as many milestones as possible before tomorrow's landing. There is still a lot that we need to learn and data that we need to collect."
Jim Chilton, senior vice president of Boeing’s Space and Launch Division : "One of the biggest things we've learned is how good this NASA/Boeing team is. Their reaction and professionalism has been inspiring. The vehicle status is excellent. Life support looks great. Power is neutral or better. We have full attitude control. We are going to get an enormous amount of data. Rosie the Rocketeer is collecting data in the capsule.
"From a flight test standpoint, it is a brand new system. The two most difficult parts of the mission are launch and landing. We had a successful launch. In space, we've been ticking off some objectives. The spacecraft has established a link with the International Space Station (ISS). The navigation system, optically looking at the stars can figure out where it is and orient itself. We've extended and retracted the docking system. There is a longer list. Not all objectives are created equal. We have a great proportion of the objectives for in space. The entry, descent, and landing is not for the faint of heart. We have not tested entry before. We still have something to prove on entry tomorrow.
"Our best understanding 24 hours later: our spacecraft needs to reach into the Atlas V rocket to get the mission time. Our spacecraft needs to reach down into the Atlas-V and figure out what time it is. Where is the Atlas-V in its mission profile and then we set the clock based on that. Somehow we reached in there and grabbed the wrong spot. This doesn't look like an Atlas problem, it looks like we reached in and grabbed the wrong coefficient. As a result of starting the clock at the wrong time, the spacecraft upon reaching space thought she was later in the mission, and being autonomous, started to behave that way. It wasn't in the orbit we expected without the burn and it wasn't in the attitude we expected, and was in fact adjusting that attitude. Yesterday, I talked about the delay we had of some minutes in linking to the tracking data relay satellites (TDRS), we think that the combination of getting between a couple satellites but more so, we were moving the vehicle and not in an attitude to get an easy link, so we think that contributed to the delay. The engineers spent the night analyzing sensors and thrusters. We might have a few remaining sensor problems, but all of the propulsion is still functioning. There is one manifold on the Service Module that is out of propellant. We can land without the RCS thrusters on that manifold. But over night tonight, we plan on executing a series of valve opening and closings to get propellant to that manifold.
"We had an unexpected event and our team reacted admirably. We look forward to getting Starliner home and saying hello to Rosie."
Steve Stich, deputy manager of NASA’s Commercial Crew Program: "This fairly stressful timing issue has caused our teams to work closer than ever. Yesterday, the team optimized the orbit and did two burns. Those two burns give us a lot of confidence as we come up to entry. The spacecraft from a NASA perspective is working really well. The interior of the cabin temperature has been perfect for the crew. All of the systems that we need for a crewed mission are working as we expected. The power margins are good. We are pointing at the Sun with the solar arrays and that is working better than expected. We are setting up for an entry on orbit #33 tomorrow. The NASA teams and Boeing teams are at the landing site now preparing for landing. I would say, so far, it has been a great mission. The ascent and launch went very well. Now we are going to embark on a very tough phase, with the reentry burn, the service module jettison and the parachutes deploying."
The first landing opportunity is at 5:57 AM MST at Boeing's landing site at White Sands Space Harbor on the White Sands Missile Range in New Mexico, with a backup opportunity at the same site at 1:48 PM MST. The spacecraft will be on an ascending approach, over the Baja Peninsula and just west of El Paso Texas. This is the same approach that was planned had the spacecraft reached the ISS. The landing will be covered on NASA TV on Sunday starting at 6:45 AM Eastern.
Late yesterday and overnight, flight controllers completed the below activities:
- Conducted two orbital adjustment burns and several smaller checkout burns of the propulsion systems
- Tested Guidance, Navigation and Control hardware including successfully using VESTA camera star tracking functionality to augment Space-Integrated GPS/INS (SIGI) navigational control. These are the “eyes” of the vehicle, which include using star trackers (capturing spacecraft orientation by comparing known star maps to stars the spacecraft observes) and far and near field observations.
- Observed positive performance of Environmental Control and Life Support Systems and executed cabin fan switching
- Communication, commanding and tracking systems testing through both ground links and space-to-space communication, including a positive command uplink from mission control through the International Space Station
- Station keeping and attitude control demonstrations
Throughout the day on Dec. 21, Starliner will attempt to complete NASA docking system checkouts and extension of the soft-capture system and docking ring.
Starliner will retain priority on the TDRS satellite network and Mission Control Center communications channels to ensure data uplink and downlink throughout the remainder of the mission.
For an overview of the re-entry burn and landing, read What to Expect During Sunday's Starliner Landing at White Sands Missile Range.
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