화성 암석 회수, Martian rock recovery

 

 

NASA는 화성에서 수집한 암석 샘플을 지구로 가져오는 미션에 대해 처음 제시됐던 회수 방법보다 비용을 크게 줄인 2가지 선택지를 새롭게 제시했다. 선택은 차기 정부에 맡길 예정이다.

NASA의 화성 탐사 로봇인 '퍼시비어런스'는 2021년 2월 화성 예제로(Jezero) 크레이터에 도착한 이후 생명체의 흔적을 찾는 탐사 활동을 수행 중이다. 거대한 크레이터 안쪽에서 과거 화성에 흘렀을 것으로 추정되는 강의 흔적 등을 조사하며 주요 위치의 암석 샘플을 수집하고 있다.

퍼시비어런스가 수집한 화성 암석 샘플은 후속 화성 착륙선 임무를 통해 지구로 회수된다. 지구와 달이 아닌 천체에서 물체를 운송하는 시도는 처음이다. 기존 회수 계획의 예산 추정치는 지난해 기준 110억 달러(약 16조원) 수준으로 경제적 부담이 매우 크다. 처음 계획에서는 화성 암석 샘플이 지구에 도착하는 시점을 2031년으로 계산했지만 기술적 어려움 등에 부딪치며 2040년까지 연기됐다. 

NASA는 화성 암석 샘플의 회수 시기를 앞당기고 비용을 줄이기 위한 방안 2가지를 새로 제시했다. 화성 표면에서 화성 궤도로 샘플을 옮기는 로켓이 기존 설계처럼 크고 무거울 필요가 없다는 점이 핵심이다.

첫 번째 방법은 퍼시비어런스를 화성에 내렸던 '스카이 크레인' 재활용이다. 공중에 떠 있는 로켓에서 케이블로 물체를 천천히 올리거나 내리는 방식이다. 크레인의 크기만 20% 가량 키워 재사용한다는 계획이다. NASA는 스카이 크레인 대신 민간 기업의 착륙선을 구매하는 두 번째 방안도 함께 냈지만 구체적인 내용은 밝히지 않았다.


스카이 크레인을 재활용했을 때 66~77억 달러(약 9조5900억~11조1900억원), 민간 착륙선을 활용했을 때 58~71억 달러(약 8조4300억~10조3200억원)의 비용이 예상됐다. 여전히 천문학적인 금액이긴 하지만 16조원 수준의 기존 계획보다는 수십억 달러 저렴하고 샘플의 지구 도착 시점을 2035년까지 앞당길 수 있다는 설명이다. 

NASA는 미국 의회에서 충분한 자금을 지원한다면 샘플 귀환 착륙선이 2031년 발사돼 2035년까지 지구에 샘플을 가져올 수 있을 것으로 전망했다. 자금 조달이 여의치 않으면 2040년까지 연장될 수 있다고도 덧붙였다. 중국은 2031년에 화성 암석을 지구로 회수하겠다고 발표한 바 있다.

NASA는 '트럼프 2기' 중인 2026년 하반기에 화성 샘플 회수 방법을 확정할 계획이다. 다만 이번에 발표된 NASA 계획은 이달 말에 임기가 끝나는 빌 넬슨 NASA 국장 임기 중 결정된 내용으로 불확실성이 존재한다. 트럼프 정부가 출범하고 재러드 아이작먼 차기 NASA 국장이 부임하면 화성 탐사 계획 자체가 바뀔 가능성도 있다.

 

 

NASA has proposed two new options for a mission to bring back rock samples collected from Mars to Earth, significantly reducing costs compared to the method of retrieval that was first proposed. The decision will be left to the next government.

Since arriving at the Jezero Crater in February 2021, NASA's Mars rover, Perseverance, has been conducting exploratory activities to search for signs of life. Inside the huge Crater, they are collecting rock samples from major locations, examining traces of rivers that are believed to have flowed to Mars in the past.

The Mars rock samples collected by Perseverance will be returned to Earth through subsequent missions of the Mars lander. It is the first time that an object has been transported from a celestial body, not from the Earth and the Moon. The previous budget estimate for the recovery plan is 11 billion dollars as of last year, which poses a heavy economic burden. The initial plan calculated the time when the Martian rock samples arrive on Earth in 2031, but the plan was postponed until 2040 due to technical difficulties.

NASA has proposed two new ways to accelerate the retrieval of Martian rock samples and reduce costs. The key point is that rockets that transfer samples from the surface of Mars to Mars orbit do not have to be as big and heavy as previously designed.

The first method is recycling the "Sky Crane," which landed the Perseverance on Mars. It is a method of slowly lifting and lowering objects from the airborne rocket to the cable. The plan is to increase the size of the crane by 20 percent and reuse the same. NASA also proposed a second plan to purchase a lander from a private company instead of the "Sky Crane," but did not elaborate.


It was expected to cost between $6.6 and $7.7 billion (about 9.59 trillion and 11.19 trillion won) when recycling sky cranes and $5.8 to 7.1 billion (about 8.43 trillion and 10.32 trillion won) when using private landers. Although it is still an astronomical amount, it is billions of dollars cheaper than the existing plan of KRW 16 trillion, and it can advance the arrival time of samples to Earth by 2035.

NASA predicts that if sufficient funding is provided by the U.S. Congress, a sample return lander could be launched in 2031 and brought back to Earth by 2035. It also added that it could be extended to 2040 if funding is not available. China announced that it would return Mars rocks to Earth in 2031.

NASA plans to confirm the method of collecting samples from Mars in the second half of 2026, during the second phase of Trump's term. However, uncertainties exist as the recently announced NASA plan was decided during the term of NASA Director Bill Nelson, whose term ends at the end of this month. There is a possibility that the plans to explore Mars will change when the Trump administration takes office and Jared Isaacman, the next NASA director, takes office.