출처 : youtu.be/M4tdMR5HLtg
"7 Minutes of Terror"
2월 18일 역사적인 순간이 있었다.
외계 생명체의 존재 가능성, 인류의 궁금증을 해결하기 위해 Perseverance Rover가 화성 (Mars)으로 보내졌다.
수개월에 거친 항해를 거쳐, 드디어 화성에 도착했다.
하지만 하나의 큰 관문이 남아 있었다. 그것은 7분의 테러 (7 minutes of terror)이다.
화성의 대기를 통과하기 위해서 굉장히 높은 속도 시간당 12,000 ~ 13,000 마일이 필요하지만
착륙하기 위해서는 그 속도를 낮춰야 한다.
그 속도를 낮추기 위해서는 낙하산 (the biggest supersonic parachute) 을 이용하였다.
문제는 그것이 원격으로 조절하기가 불가능하다는 것이다.
그것은 NASA에서 쏘아 보낸 비행체가 스스로 해야 한다 (The spacecraft has to do all of this by itself) .
계획된 시나리오대로 움직여야만 안전한 착륙이 가능하다.
화성 대기를 통과해서 착륙하기까지의 시간, 7분
(seven minutes to get from the top of the atmosphere of Mars to the ground safely).
Perseverance Rover의 착륙예정지는 "Jezero Crater" 로 ancient lakebed이다.
이 Rover의 일차 목표는 미생물의 존재 가능성을 확인하는 것이고,화석 같은 형태로 미생물이 있을 것 같은 장소로 Jezero Crater를 택한것이다.Rover는 그 위치에서 샘플을 취해서 지정된 장소에 보관하고, 나중에 다른 우주선(?)을 통해서 지구로 보내질 것이다 (
The science team identified Jezero Crater as basically an ancient lakebed.
One of the most promising places to look for evidence of ancient microbial life
and to collect samples for future return to Earth)
미국 NASA에서 얼마나 치밀하게 준비했는지가 담겨져 있다.
Nothing can be taken for granted when you get to Mars.
There’s a lot of things we just don’t know.
Space always has a way of throwing us curveballs and surprising us.
I mean, until we get the data that says we’re on the ground safely
I’m gonna be worried that we’re not gonna make it.
PERSEVERANCE’S ENTRY, DESCENT AND LANDING
Entry, Descent and Landing is often referred to
as the "seven minutes of terror".
Because it takes about seven minutes
to get from the top of the atmosphere of Mars to the ground safely.
The spacecraft has to do all of this by itself.
There are many things that have to go right to get Perseverance
onto the ground safely.
There’s a lot counting on this.
This is the first leg of our sample return relay race.
There’s a lot of work on the line.
Starting about ten minutes before atmospheric entry,
we get rid of really the spacecraft part of the rover that’s been supporting us.
We come screaming into the Martian atmosphere at twelve to thirteen thousand miles per hour.
And the heat shield is what dissipates all that initial energy through friction.
The vehicle will continue actually flying itself through the atmosphere.
It’s sort of like a transforming vehicle that went from spacecraft
and now it’s kind of like an aircraft actively guiding itself.
When we’re going slow enough we deploy a parachute.
It’s the biggest supersonic parachute we’ve ever sent to another planet.
It’s critical for slowing down the vehicle.
Perseverance’s Entry, Descent and Landing borrows heavily from that of Curiosity.
But fundamentally, Perseverance is a different rover
She’s bigger, she has different instruments.
We’ve added a lot of smarts on the inside to make it more capable
so that it can deal with the landing site that we’ve given it.
The science team identified Jezero Crater as basically an ancient lakebed.
One of the most promising places to look for evidence of
ancient microbial life and to collect samples for future return to Earth.
The problem is it’s a much more hazardous place to land.
When you look at Jezero, all you see is danger.
How do we go to a site that we never thought was safe enough to go to before?
So the heat shield, which has protected us all the way through entry,
is no longer necessary.
We need to get that off so we can actually see the ground.
And we can see the ground in a couple of different ways.
Perseverance will be the first mission to use Terrain Relative Navigation.
So while it’s descending on the parachute,
it will actually be taking images of the surface of Mars and determining where to go based on what it sees.
This is finally like landing with your eyes open.
Having this new technology really allows Perseverance to land
in much more challenging terrain than Curiosity or any previous Mars mission could.
Amongst the rocks and the craters and the cliffs,
these things are hazardous to the rover but these are the things
that are interesting to the scientists.
Once Perseverance has figured out where she is,
we jettison the backshell and the parachute, and light up our rockets.
Those rockets help us steer to a safe landing spot that’s nearby.
That descent stage takes us all the way down to about twenty meters off the ground.
That’s when we start the skycrane maneuver.
Once the rover has hit the ground, the descent stage will cut loose from the rover and fly away to a safe distance.
Surviving that seven minutes is really just the beginning for Perseverance.
It’s job, right, being the first leg of sample return to go look for those signs of past life on Mars
All that can’t start until we get Perseverance safely to the ground.
And then, that’s when the real mission begins.
[LANDING ON MARS FEBRUARY 18, 2021]
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take for granted : ...을 당연시하다. 당연히 ~ 일 것이라고 믿다 |
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