George Diller: Here with us now in the Mission Director's Center is Jim Snoddy, the DART project manager
from the Marshall Space Flight Center in Huntsville. Jim, first of all, give us a quick status. At departure,
how did DART look, how did MUBLCOM look, and how about our tracking stations around the world to support
after we get under way with the mission? Jim Snoddy: Everything from DART has been going excellent.
All our tracking stations from Alaska to Antarctica to Norway are all up and operational.
Our MUBLCOM tracking station in Dulles in Virginia is up and operational. Everything from DART
looks excellent at this point, so we're ready and excited for a successful mission today.
Diller: Alright. Well, we have some animation now that, we can roll that, that'll show us what's
actually going to happen beginning with the... Snoddy: This is animation of four minutes of DART.
This is the entire mission. You can see the Pegasus solid rocket under the L-1011 as we're
currently out going over the ocean. Now in the process of dropping the Pegasus launch vehicle,
and for about 720 seconds, the solid rocket motors will be firing to get DART into its required
orbit to go do its rendezvous. The picture now has the MUBLCOM satellite, which is the target satellite
we're going to go do our proximity operations and demonstrate the technology for the DART mission.
Now we're back to the Pegasus launch vehicle firing, going through all the various stages to give us
the orbital velocities to get us into orbit. Here we go. The DART vehicle coming out.
And we're currently doing the rendezvous mission to catch up with the MUBLCOM.
DART's chasing it, coming up from behind. We always want to make sure we maneuver from behind to
catch up with the existing satellite. So we're doing all our hydrazine burns to catch up.
And now you can see the DART spacecraft is still looking for the MUBLCOM satellite,
firing the hydrazine propulsion systems and looking. You can see the Sun coming over the horizon.
And we're again circling the Earth several times to make these rendezvous burns.
These are called transfer-stage burns to get us to the right orbital altitude where the MUBLCOM is.
This will go on for approximately about seven hours today, until we actually catch up to the existing satellite.
So we'll make these burns intermittently through the day, and then about eight hours from the time we finish
the Pegasus burns, we'll be looking for the MUBLCOM satellite. As you can see now,
the DART spacecraft uses GPS to locate things in space, and these are all the various GPS locations
we're using to find the MUBLCOM satellite. Now DART is currently now at 3,000 meters and approaching
the MUBLCOM satellite. You can see the MUBLCOM satellite now that has all its GPS locations and those are
transmitting back and forth between the satellite and the spacecraft to rendezvous these two objects in space.
You can see now the DART spacecraft is approaching the MUBLCOM at about 1,000 meters
and now it's at 300 meters, and we're starting to do all the maneuvers, and we're switching over from
the Global Positioning System to the advanced video guidance sensor, which is one of
the key technologies of DART, to precisely locate an object and bring you in within five meters of this object
that's currently orbiting the Earth, that we call MUBLCOM.
And here we are doing the circumnavigation, we're doing a 360-degree, going around the existing satellite
to demonstrate all the maneuvers in space that are required to autonomously rendezvous and dock with
the objects in space. And again, as you can see on the range, it's showing 1,000 meters,
so we're currently doing a station at 1,000 meters, rotating around the vehicle, and DART will go through
all these operations two or three times to demonstrate the technology.
We actually plan to go through all these steps twice to repeat that through the mission.
The mission will last 24 hours and we'll go through approaching it from the X direction,
the Y direction, we'll do collision avoidance maneuvers to show that we can lose contact with it
and reacquire. Now you can see the AVGS, which is the simulation of the white signals going back and forth,
to show that we can talk to the satellite, and it's beaming back, so... Now we're at 500 meters,
we're backing out, and now we're starting to approach again from 300 meters, and go through the,
to the satellite, what we call our station-keeping maneuvers.
Now we've reversed the axis and we're going beneath the satellite and doing a rotation around the satellite.
And we'll come out 100 meters for that, and we're currently doing the station keeping to prove
that we can stay at an equal distance from the satellite and hold our position.
And again, you can just see we're going over the Earth, MUBLCOM's going about 17,000 miles an hour,
so we're doing this with this object moving 17,000 miles an hour, and we're circling around
that and holding our distances anywhere from 1,000 meters all the way down to five meters.
Now DART's reorienting itself to put itself to put its vector toward the Earth,
so it can fire the hydrazine system and put ourselves what we call the departure point of the mission
and go into retirement burn now that we've satisfied all our objectives, and we're putting it
into an orbit where it'll eventually burn up in the Earth within the next 10 years.
Diller: Jim, after the spacecraft comes off the Pegasus rocket, what's the first thing you'll be looking for
that lets you know that the satellite is healthy and where it should be?
Snoddy: Once the, after the 700 seconds of the Pegasus firing, we will do an on-orbit health check
where we bring all of our instrumentations up. We'll make sure all the sensors are working
and do that, that lasts for about 30 minutes. Then after that 30 minutes, then we go into the hunt
and start looking for the MUBLCOM satellite. And that's, that takes us to six to eight hours
to go catch up with the day. That depends on which day you go, and based on launching from
from Vandenberg and orbital mechanics, it's going to take us about eight hours today to catch up
with that satellite. And after that, we'll do some hydrazine burns, and then we'll start doing
the real science of DART, about after eight hours today, we'll start that.
Diller: And the mission itself, once you begin these rendezvous proximity operations, how long is the mission?
Snoddy: The mission is totally, it's totally 24 hours. That's how much propellant we've put on the mission
with adequate reserve. So it's totally 24 hours, and the first eight is actually the technology of using
GPS and trying to catch up with it. And then we really get into the real, how well does this sensor work
to locate objects within four or five meters within space, with millimeters of accuracies to be able
to show that we can demonstrate the technology of docking two objects in space eventually.
Diller: After the mission's over, what happens to DART? What happens to MUBLCOM?
Snoddy: MUBLCOM is an existing satellite. It was put up under a Department of Defense program back in 1999,
so it's basically a retired satellite. So NASA is utilizing that free asset, so it'll just,
it'll continue in its orbit. Once DART, after the 24-hour mission, as you've seen in the video,
we'll reorient ourselves back toward the Earth, and we, we do not, we don't create space debris,
so we put it and fire the hydrazine system which is also the fourth stage that put us into orbit,
so we're using that for dual purposes to fire that and put is in a unstable orbit. So it'll eventually
burn up within, the requirement's to burn up within 25 years. We're satisfying
that requirement within 10 years. So DART would eventually just burn up.
George Diller: What happens in terms of ultimate technology benefit that NASA achieves?
What do we really hope that this can give the Agency the capability to do?
Jim Snoddy: DART, DART is really, it's kind of got twofold. One is that you've got to have a brain
to go calculate all these maneuvers. You've got to be able to maneuver in space and control your,
your thrusters, your arms and legs, and have a brain to figure all that out. So DART's what we call the
automated rendezvous and proximity operations technology, the ability to have the
system engineering aspect to put all that together. And we're also demonstrating what we call
the advanced video guidance sensor, which we've had to create. GPS gets you in the neighborhood,
and then you've got to transition something to a precise, you know, get things down
to the millimeters and get things really close in space. So the AVGS will be demonstrating
the technology that we've created, this eye that can calculate distances precisely, so we can one day
put objects together in space for the president's initiative to go to the Moon and to Mars.
The more, the more things we put into space, the more autonomous operations, we can bring cost down,
we can create almost like an autopilot to put things in space one day and, and bring these objects together.
Diller: Well, thank you, Jim. And we'll be looking forward to the next seven hours
and then the next day, so thank you very much. Snoddy: Thank you.