中國(guó)首個(gè)火星探測(cè)器發(fā)射升空

曹希

On July 23， 2020， China successfully set off its first fully homegrown Mars mission， the Tianwen-1， on to a monthlong space voyage toward the Red Planet， marking a new era in a space exploration sector long dominated by NASA.

Tianwen-1， which translates to “heavenly questions”1， consists of an orbiter and a lander/rover duo. Its the first attempt by any country to achieve orbiting， landing and roving all in one go. “No planetary missions have ever been implemented in this way. If successful， it would signify a major technical breakthrough，” scientists of the China National Space Agency （CNSA） wrote in a recent paper on Nature Astronomy outlining the missions objectives.

The orbiter， lander and rover probe combo lifted off atop a Long March 5 rocket from the Wenchang Satellite Launch Center on Hainan Island Thursday morning at 12：41 a.m. EDT2. American space entrepreneur and Mars enthusiast Elon Musk praised the mission in a tweet Thursday morning， calling the launch “impressive.”

Impressive Tianwen-1 Mars rover mission launched by China today https：//t.co/FsyA3I0HrU

— Elon Musk （@elonmusk） July 23， 2020

Four days ago， the United Arab Emirates launched its own Mars orbiter， Hope， atop a Japanese rocket to study the Red Planets atmosphere and climate. Taking advantage of the summer launch window， NASA will launch a Mars probe as well， the life-hunting Perseverance rover， on July 30. All three missions are scheduled to arrive at Mars in February 2021.

What will Tianwen-1 do on Mars？

In the Nature Astronomy paper， CNSA researchers laid out five scientific objectives of the Tianwen-1 mission： Map the geological structure of Mars， investigate surface soil characteristics， analyze surface material composition， and study the Martian climate and environment at the surface， as well as the physical fields （electromagnetic， gravitational） and internal structure of Mars.

If all goes according to plan， the Tianwen-1 probe will reach Mars orbit in February next year. The orbiter will settle into a polar elliptical orbit that will allow it to observe the planets surface from a height between 165 miles and 7，500 miles.

The rover is expected to touch down on the Martian surface in April or May somewhere within Utopia Planitia， a large plain in Mars Northern Hemisphere. Once deployed， the rover will spend about 90 Martian days （or 93 Earth days） studying its surroundings in detail.

What else is on Chinas space playbook？

The Tianwen-1 mission is Chinas second attempt at the Red Planet after a 2011 orbiter mission called Yinghuo-1 failed. The Yinghuo-1 mission didnt include a lander or a rover.

China has been a frontrunner in pushing space projects over the past two decades. As The New York Times noted， the countrys space program is “one of the few that have launched their own astronauts and space stations to orbit.” China is also the first country to land a probe on the far side3 of the moon. Last January， CNSA successfully sent a robotic lunar rover called Yutu-2 to the moon as part of the Change-4 mission4. The rover is still roaming the dark side of the moon studying the lunar composition.

2020年7月23日，中國(guó)完全自主研發(fā)的天問(wèn)一號(hào)火星探測(cè)器成功發(fā)射升空，開(kāi)始了為期數(shù)月的太空之旅，奔向火星。中國(guó)開(kāi)啟首次自主火星探測(cè)任務(wù)，標(biāo)志著長(zhǎng)期以來(lái)由美國(guó)國(guó)家航空航天局主導(dǎo)的太空探索進(jìn)入了新紀(jì)元。

“天問(wèn)”可解讀為“向上天叩問(wèn)”。天問(wèn)一號(hào)火星探測(cè)器由環(huán)繞器和著陸巡視器組成。在中國(guó)之前，還沒(méi)有哪個(gè)國(guó)家嘗試過(guò)一次完成繞飛、著陸和巡視三大任務(wù)。中國(guó)國(guó)家航天局的科學(xué)家們最近在《自然·天文學(xué)》雜志上發(fā)表論文概述了這次探測(cè)任務(wù)的目標(biāo)，其中寫(xiě)道：“以往的行星探測(cè)任務(wù)從未這樣做過(guò)。如果成功，這將標(biāo)志著一項(xiàng)重大的技術(shù)突破?！?/p>

美國(guó)東部夏令時(shí)間7月23日凌晨0點(diǎn)41分，探測(cè)器搭乘長(zhǎng)征五號(hào)運(yùn)載火箭從中國(guó)海南文昌航天發(fā)射場(chǎng)升空。美國(guó)航天企業(yè)家埃隆·馬斯克也是一名火星愛(ài)好者，他在周四上午發(fā)推特稱贊這次發(fā)射 “十分震撼”。

今天中國(guó)的天問(wèn)一號(hào)火星探測(cè)器發(fā)射了，十分震撼https：//t.co/FsyA3I0HrU

——埃隆·馬斯克（@elonmusk）2020年7月23日

4天前，阿拉伯聯(lián)合酋長(zhǎng)國(guó)的希望號(hào)軌道器搭乘日本制造的火箭發(fā)射，任務(wù)是研究火星的大氣和氣候。美國(guó)國(guó)家航空航天局也將利用夏季發(fā)射窗口，于7月30日發(fā)射毅力號(hào)火星探測(cè)器，尋找火星上的生命跡象。三項(xiàng)任務(wù)的探測(cè)器均計(jì)劃于2021年2月抵達(dá)火星。

天問(wèn)一號(hào)將在火星上做什么？

在《自然·天文學(xué)》雜志上發(fā)表的論文中，中國(guó)國(guó)家航天局的研究人員列舉了天問(wèn)一號(hào)探測(cè)任務(wù)的五個(gè)科學(xué)目標(biāo)：繪制火星地質(zhì)結(jié)構(gòu)圖，調(diào)查火星表面土壤特征，分析火星表面物質(zhì)組成，研究火星表面的氣候和環(huán)境，以及研究火星的物理場(chǎng)（電磁場(chǎng)、引力場(chǎng)）和內(nèi)部結(jié)構(gòu)。

如果一切按照計(jì)劃進(jìn)行，天問(wèn)一號(hào)探測(cè)器將于2021年2月到達(dá)火星軌道。環(huán)繞器將最終進(jìn)入火星的極地橢圓軌道，這樣就能從165英里到7500英里的高度觀察火星表面。

巡視器預(yù)計(jì)于4月或5月著陸，著陸地點(diǎn)在烏托邦平原，那是火星北半球的一個(gè)大平原。部署完畢后，巡視器將用大約90個(gè)火星日（即93個(gè)地球日）詳細(xì)研究周圍的環(huán)境。

中國(guó)還有什么航天計(jì)劃？

天問(wèn)一號(hào)火星探測(cè)任務(wù)是中國(guó)第二次嘗試飛向火星。2011年，中國(guó)的螢火一號(hào)火星探測(cè)任務(wù)遭遇失敗，該任務(wù)沒(méi)有配備著陸器和巡視器。

過(guò)去20年，中國(guó)始終是航天項(xiàng)目的領(lǐng)跑者。正如《紐約時(shí)報(bào)》所指出的，中國(guó)的航天項(xiàng)目是“為數(shù)不多將本國(guó)宇航員和空間站送入軌道的”。中國(guó)也是第一個(gè)完成月球背面著陸的國(guó)家。2019年1月，中國(guó)國(guó)家航天局成功將玉兔二號(hào)月球巡視器送上月球，那是嫦娥四號(hào)探月任務(wù)的一部分。玉兔二號(hào)巡視器目前仍在月球暗面漫游，研究月球的構(gòu)成成分。? ? ? ? ? □

（譯者單位： 對(duì)外經(jīng)濟(jì)貿(mào)易大學(xué)）