Asteroid Hunting

01OSIRIS-REx is a grand adventure of exploration in deep space.

02We built a robotic spacecraft, and we launched it off the Earth, and we sent it to a near-Earth asteroid named Bennu.

03This is NASA's curious universe.

04Our universe is a wild and wonderful place.

05I'm Patti Boyd, and in this podcast, NASA is your tour guide.

06NASA has sent a robotic spacecraft billions of kilometers from Earth to do something we've never done before, collect a sample of an asteroid.

07In this episode, we're exploring asteroid Bennu, the target of our OSIRIS-REx mission.

08October 20, 2020, is the culmination of an enormous amount of work by thousands of people all around the planet.

09We are getting ready to send our spacecraft down to the surface of asteroid Bennu to collect our sample.

10That's Dante Loretta.

11He's the principal investigator on the OSIRIS-REx mission.

12He's been with the team since the very beginning, 2004, preparing for this exact moment.

13Our goal is to get the treasure off the surface of that asteroid.

14We're scientists, and we're geologists, and our treasure is in the form of rocks.

15But these aren't just any rocks.

16These are very special rocks.

17These are rocks that are older than the Earth that date from the formation of the solar system, and they hold clues to why the Earth is a habitable planet, why we have oceans here, and maybe why the origin of life occurred.

18So we have the amazing objective of bringing those rocks back to the surface of the Earth so we can get them into our laboratories and study them in great detail.

19It's the first time an American spacecraft will attempt to collect a sample of an asteroid and deliver it to Earth.

20Scientists hope OSIRIS-REx will bring back the largest cache of dirt from space in half a century.

21Like moon soil from the Apollo era that scientists are still analyzing in their labs today, soil from Bennu will be preserved for decades to come.

22Future generations will have a chance to analyze it.

23People not yet born.

24Using techniques not yet invented.

25Answering questions we don't even know to ask yet.

26And scientists like Dante can't wait to get their hands on these samples.

27Studying asteroids is important for a few key reasons.

28One is they are the oldest geological samples from the formation of the solar system.

29Literally the oldest rocks that formed around the sun are found in asteroids.

30So what would NASA want with a bunch of old rocks?

31Well, analyzing those ancient rocks will help scientists understand the early solar system in a way that studying Earth rocks can't.

32Those rocks don't exist on the surface of the Earth because the Earth is a very active geologic body.

33It's got volcanoes.

34It's got rain.

35It's got erosion.

36It's got plate tectonics.

37So these rocks and the asteroids, they're over 4.5 billion years old.

38There's nothing that old on the surface of the Earth.

39Bennu is a deep space time capsule, a leftover fragment from the tumultuous formation of the solar system.

40It's been well preserved in the vacuum of space for billions of years.

41Some of the mineral fragments inside Bennu could be older than the solar system.

42These microscopic grains of dust could be the same ones that spewed from dying stars and eventually coalesced to make the sun and its planets nearly 4.6 billion years ago.

43Bennu's makeup excites scientists.

44It's thought to be rich in organic molecules which are the building blocks of life on Earth.

45And it's got the ingredients of another very important molecule locked inside its minerals.

46And you'd probably be surprised, but it's water.

47Water in space is incredibly valuable for a couple of reasons.

48Primarily, you can break it apart and make liquid hydrogen and liquid oxygen.

49And that is one of the most powerful rocket fuels that we know of.

50The presence of water ingredients on Bennu means that one day we may be able to use asteroids like space gas stations.

51You could have a spacecraft that's using liquid hydrogen and liquid oxygen and then it could stop at Bennu and get refueled or you could bring that fuel back even to around the moon or near Earth orbit and you could use it to refuel vehicles there.

52Studying Bennu will also help scientists understand the hazards of near-Earth asteroids.

53Bennu is also what's called potentially hazardous, which means it has a reasonably high probability of impacting the Earth in the future, creating a widespread natural disaster.

54And I don't want anybody to panic because the impact would be not for at least 150 years, but still, it's something I feel as a species we should be studying.

55Bennu is one of the most potentially hazardous near-Earth objects currently known.

56It's as wide as the Empire State Building in New York City is tall.

57And it has about a 1 in 2,700 chance of impacting Earth sometime between the years 2175 and 2199.

58Our ability to make a detailed study of the asteroid now helps us prepare for the future should Bennu stay on a course towards Earth in the next century.

59It's kind of a gift to the future to go out and characterize this object because it's likely that at some point in the future, maybe within the next 100 years, some group of people are going to have to figure out how to deflect this asteroid and prevent it from impacting the Earth.

60There's a lot of information locked up in the rocks and dirts on Bennu's surface.

61But before scientists on the ground get the opportunity to study those samples, OSIRIS-REx has to collect them.

62The spacecraft launched in 2016 from NASA's Kennedy Space Center in Florida with this goal in mind.

63Go Atlas.

64Go Centaur.

65Go OSIRIS-REx.

66Everyone is go.

67Standing by for launch.

68And liftoff of OSIRIS-REx, its seven-year mission to boldly go to the asteroid Bennu and back.

69Since launch day, OSIRIS-REx has had its eye set on asteroid Bennu.

70For two years, it's made its way to the asteroid and has been in orbit ever since, circling the asteroid and mapping its surface in great detail, all in preparation for October 20th, the day it will attempt to grab a sample from the surface.

71On the ground, OSIRIS-REx engineers like Ron Mink have been preparing too.

72As a systems engineer, part of my job is to identify the bad things that could happen and to prepare for them.

73And so I'm thinking about risk all the time.

74Now, Bennu, the asteroid, hasn't been very compliant with what we need its surface to be.

75We first saw the asteroid in August of 2018, and that was one of the most exciting days of my life.

76Something I'd been planning for well over a decade was finally coming into focus.

77Literally.

78I could see the target.

79And then the asteroid got more and more resolved, and I just had this sinking feeling in my stomach because the surface looked really rough, rugged, and rocky, and not what we were expecting.

80Our sample collector, we need to have, you know, particles that aren't much more than an inch in size to be collected.

81And there aren't very many places on Bennu that have grains that small.

82And so we think we found the sweetest spot on the asteroid, and we're going to go there.

83But Bennu may not want to give up her secrets.

84That's probably my biggest concern.

85We've done everything we can, but that's part of exploration.

86Space exploration means being vulnerable, and sometimes trying things that no one has tried before.

87The OSIRIS-REx team has done everything they can to prep the spacecraft for its sample collection.

88They've even gone through rehearsals for the big day.

89Finding the right spot, one that's clear of boulders, is key.

90It wasn't easy, but the team found such a spot.

91They called it Nightingale.

92It's a 52-foot-wide, relatively clear area inside a crater, a rare sighting on Bennu.

93And if Nightingale doesn't work out, the mission team picked a backup site, dubbed Osprey, where they can try for the second and final time to pick up a sample.

94These sites have the most evidence for fine-grained material on the asteroid, and give OSIRIS-REx the best shot at collecting a sample.

95After years of hard work, the big day is here.

96If OSIRIS-REx succeeds in its mission, scientists will get the opportunity to unlock secrets of the early solar system.

97Even though the talented team is prepared beyond question, in space there's always a risk that things might not go according to plan.

98Even though we found a nice spot where we think there's lots of material that we can collect a sample from, there's still some pretty big rocks around that site.

99The biggest one I call Mount Doom.

100It's about 10 meters tall, and it's just off to the east of the crater, and we absolutely do not want to fly into that.

101We don't know what's going to happen when the spacecraft touches the asteroid's surface.

102One of the things that might happen is it might tip over and start to move in another direction, and then it fires its engines to leave the asteroid's surface.

103It could fly right into Mount Doom if it did that, if it tipped over too much.

104If the team can safely capture samples from Bennu, there's a huge payoff.

105For Dante and the team, there's a lot riding on this moment.

106It's the culmination of many years of hard work for an entire team.

107On Sample Collection Day, the stakes are high.

108We are getting ready to send our spacecraft down to the surface of asteroid Bennu to collect our sample.

109As you can imagine, there's a lot of excitement, there's a lot of anxiety, and there's a lot of nervousness to make sure everything goes according to plan.

110I've been working on this program since 2004.

111Almost 17 years of my career has been focused on this one day to make sure everything goes according to plan.

112We have thought through everything that could go wrong on that day, and we've done our best as a team of engineers and scientists and managers to make sure we've mitigated all known risks.

113That doesn't mean that things can't go wrong still, because there's always the unknown nature of the asteroid surface and what's going to happen when we make contact.

114On the day of the sample collection, OSIRIS-REx will go through a series of carefully choreographed moves to prepare to secure rocks and soil from the surface of Bennu.

115OSIRIS-REx was designed with these steps in mind.

116So OSIRIS-REx is a robotic spacecraft, and it is designed to operate around an asteroid and eventually go down to the surface to collect those rocks.

117So there's some very special features about the spacecraft that allow us to do that.

118OSIRIS-REx has a number of science instruments on board that will do things like map the surface of Bennu and provide information about the minerals it finds there.

119It's also got cameras and sensors to help it navigate and an arm that will collect rocks and dirt from the asteroid surface.

120Even though OSIRIS-REx has the right tools to get the job done, sample collection can be pretty tricky.

121We need to get onto the surface into a parking spot size space with our spacecraft in order to collect a sample.

122And when you're doing that from 200 million miles away, it takes a lot of practice.

123That's Heather Enos.

124She's the deputy principal investigator for the mission and will walk you through the steps of OSIRIS-REx's sample collection, a process called TAG.

125So TAG is touch and go.

126And what we mean by that is literally we are reaching out with the arm of our device and we are touching and going.

127We don't land on Bennu.

128We actually literally kiss the surface with the end of the arm.

129We're kissing the surface for about somewhere between 6 and 16 seconds.

130So it's a really, you know, after all of these years, it really all happens in less than 20 seconds.

131But leading up to that moment, Heather and the team will observe as OSIRIS-REx swoops closer and closer to the asteroid's surface, preparing to make contact.

132The day of TAG, it's about a four and a half hour sequence, we call it, and we will leave orbit.

133Currently, we're in a safe home orbit, we call it, around Bennu.

134And we will command the spacecraft to get out of its orbit and start to slowly descend onto the surface of Bennu.

135The spacecraft is going to fire its thrusters and leave orbit and very slowly approach the surface of Bennu, taking images along the way.

136OSIRIS-REx will use those images and compare them to an existing catalog of the site.

137This helps the spacecraft make sure it's headed in the right direction.

138The whole time, OSIRIS-REx is going through the steps on its own.

139There's no one controlling OSIRIS-REx in real time from the ground.

140All of this is preloaded, autonomous, and so once we hit go, everything becomes autonomous.

141We're going to send up a set of commands that basically tell the spacecraft what to do from leaving orbit until leaving the surface.

142So it's all, it's on all automated commands.

143We don't have a joystick, you know, or an Xbox controller here on the ground to tell the spacecraft what to do because there's going to be about a 15 to 20 minute delay in our signal.

144So we can't talk to the spacecraft in real time that way.

145It's all preplanned.

146OSIRIS-REx is fully autonomous.

147It begins to descend closer to the asteroid's surface.

148At that point, we're about 125 meters from the surface and that's our first opportunity to do our position and velocity checking and to make sure that our trajectory is on target.

149So then we would continue to go down a little bit slower, even yet, and then we do another check which we call match point and that will be at about 40 meters above the surface.

150And then we have the, what we call our TAGSAM arm, touch and go arm that is then deployed and we slowly descend to the surface.

151OSIRIS-REx will aim to collect at least 60 grams of dirt and rocks, equal to about 30 sugar packets.

152It does that by stirring up the asteroid's surface.

153Think about a reverse vacuum cleaner.

154We actually use a gas bottle of very high purity nitrogen to blow down on the surface in order to get the soil to move and to be agitated because otherwise, with no gravity, things don't move around and so we're forcing movement by blowing it down with the high purity nitrogen.

155It's a very clean, pristine gas so we're not contaminating the surface with anything we've brought along.

156After stirring up the surface, the samples will float up into a chamber.

157Once OSIRIS-REx successfully secures them, the spacecraft will slowly drift away from Bennu until it reaches a safe distance.

158And it will stay there until its departure in March 2021, preparing for its return back to Earth.

159When OSIRIS-REx reaches Earth in 2023, it will drop the capsule with the samples packed inside into Utah's West Desert, where scientists will be waiting to collect it.

160We really refer to it as the mission that keeps on giving and the reason that we call it that is we're bringing back this precious material back to Earth and it's going to then be analyzed in laboratories at the macroscopic scale that we cannot do remotely.

161And getting these samples back to Earth will be a huge deal.

162It could literally change what we know about the history of our solar system.

163That's why the day of TAG will be an emotional one for the whole team.

164To get here, it really has taken a lot of time and a lot of people's passion and a lot of sacrifice.

165So you become personally attached to the spacecraft, it becomes human, the instruments become human, and it's not just a team.

166after this many years of sharing this hard work and sacrifices and common passion with your team, it really becomes your family.

167You know, we hear a lot about the planets, you know, Mars and Venus and Mercury.

168There have been, you know, fabulous missions to all those objects and there, you know, some pretty incredible science and some incredible pictures.

169But what I love about asteroids and comets is that each one of them is their own unique small world and there are, you know, literally tens of thousands or depending on how small you want to look at, millions of them in the solar system that we can explore.

170And so, you know, I look at Bennu as not just a face rock or the flotsam left over from this formation of the solar system.

171But rather, a unique world all of its own that has its own beauty and its own secrets.

172And also, in the case of Bennu, it's its own dangers.

173Osiris-Rex, it's an extension of me in so many ways.

174it's hard to explain and it sends chills down your spine because you're like, wow, we are an amazing species.

175The human beings built this, this robot and we sent it out on this seven-year, billion-kilometer journey to go get this material so that we could study it in our laboratories.

176Osiris-Rex is all about inspiring the next generation of scientists and engineers and leaders to go after something big, whether in space exploration or in any field that you're passionate about.

177You can make it happen and when it does happen, it makes your whole life worthwhile.

178This is NASA's Curious Universe.

179The Curious Universe team includes Maddie Arnold, Michaela Sosby, Margo Wall, and Vicki Woodburn.

180Our executive producer is Katie Atkinson.

181Special thanks to Ryland Heggie, Ronnie Grahn, Nancy Neal-Jones, Lonnie Shechtman, and the University of Arizona.

182You can follow Osiris-Rex as it completes its tag attempt in real time.

183Go to www.nasa.gov slash Osiris-Rex.

184If you liked this episode, please let us know by leaving us a review, tweeting about the show at NASA, and sharing this episode with a friend.

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187You can email a voice recording or send a written note to nasa-curiousuniverse at mail.nasa.gov.

188Go to nasa.gov slash curiousuniverse for more information.

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