對宇宙間最高能粒子進(jìn)行探測是一項技術(shù)挑戰(zhàn)。把儀器設(shè)備安置在高空氣球和衛(wèi)星上帶上天空進(jìn)行的天體物理觀測實(shí)驗更加困難。如果是為了探測來自恒星和星系的X射線或γ射線輻射，這項技術(shù)就有很大的意義。地球大氣是這些種輻射的強(qiáng)吸收物，氣球或衛(wèi)星能使觀測在大氣以上進(jìn)行。另一方面，如果打算用這種辦法捕捉超高能宇宙射線，就必須有極大的耐心。能量高于1019eV的宇宙射線粒子，平均每年在1平方公里的面積上只落下一顆。換成空間觀測，利用面積為1平方米的典型衛(wèi)星探測器攔截的話，等待100萬年才有可能探測到1顆這類宇宙射線的粒子!

• ACE [Advanced Composition Explorer] Mission mainly for solar particles; launched in August 1997.

• AGILE [Astro-rivelatore Gamma a Immagini LEggero] X-ray/gamma ray mission to be launched in October 2006.

• AMS [Alpha Magnetic Spectrometer] Detector to be flown on the International Space Station

利用強(qiáng)磁場和精密探測器來探測宇宙空間的反物質(zhì)和暗物質(zhì)，探索和研究宇宙物理學(xué)、基本粒子物理學(xué)和宇宙演化學(xué)的一些重大和疑難問題的阿爾法（α）磁譜儀（Alpha Magneitic Spectrom-eter，簡稱AMS）的研制工作正在進(jìn)行。AMS是人類送入宇宙空間的第一個大型磁譜儀，這是美籍華裔物理學(xué)家丁肇中教授提出并領(lǐng)導(dǎo)的大型國際合作科學(xué)研究項目，由美國和中國等10多個國家和地區(qū)的37個科研機(jī)構(gòu)參加科研工作。

AMS由一個直徑約1.2米、高0.8米、重量約為1.85噸的圓環(huán)形永磁體產(chǎn)生均勻的平行磁場，磁束密度約為0.15特斯拉。圓環(huán)內(nèi)安裝6層硅微調(diào)探測器，用來記錄帶電宇宙射線粒子的運(yùn)動軌跡。一個帶正電荷的粒子在穿過磁場時，其運(yùn)動方向?qū)⑴c帶負(fù)電的相反。根據(jù)每層記錄下來的帶電粒子穿過的軌跡，可以推算出粒子的偏轉(zhuǎn)方向及帶電荷的大小。帶電荷量愈大，在穿過每層硅微調(diào)探測器時能量損失愈快。具有較大動量的粒子在穿過探測器時偏轉(zhuǎn)的角度較小，從而可以估計出粒子的質(zhì)量。磁譜儀的上、下兩層還裝有閃爍體，當(dāng)粒子穿過時會發(fā)出亮點(diǎn)，其亮度與粒子穿過時的能量成正比。通過上、下兩層光點(diǎn)亮度及穿過瞬間的比較，可以得出粒子能量的損失大小以及粒子穿過所需的時間。反物質(zhì)、暗物質(zhì)在磁場中運(yùn)動時會表現(xiàn)出不同的特點(diǎn)，因而可以探測出來。1998年6月AMS搭載美國"發(fā)現(xiàn)號"航天飛機(jī)成功地進(jìn)行了首次飛行，進(jìn)行了約10天的試驗性探測，取得了許多重大物理成果。計劃于2008年升空進(jìn)入由美、俄、西歐、日本和加拿大等國聯(lián)合研究的“國際空間站”進(jìn)行長達(dá)3―5年的數(shù)據(jù)采集工作。（左圖為“發(fā)現(xiàn)號”航天飛機(jī)上的AMS）

中國在這項重要的研究和應(yīng)用中也作出了重要的貢獻(xiàn)。高能所等單位承擔(dān)大型永磁體系統(tǒng)的設(shè)計、研制、測試和空間環(huán)境模擬實(shí)驗。（右圖為AMS01永磁體系統(tǒng)在北京進(jìn)行震動實(shí)驗）

AMS二期工程中高能所參加了最重的子探測器--電磁量能器AMS-02的研制。AMS-02設(shè)計載荷要求最高、最苛刻，高能所研制的初樣成功通過了空間環(huán)境模擬試驗，達(dá)到了美國NASA的技術(shù)要求，并依據(jù)所建立的有限元模型對AMS-02作了減重，對飛行件設(shè)計方案作了相應(yīng)的修正。AMS-02飛行件主體總裝和空間環(huán)境模擬試驗于2004年完成，通過了NASA專家的嚴(yán)格審查。中國在研制過程中掌握了數(shù)項國內(nèi)以往沒有成熟經(jīng)驗的先進(jìn)試驗技術(shù)及模擬計算修正技術(shù)，獲得了很高的國際顯示度。

• ASCA [Advanced Satellite for Cosmology and Astrophysics] (X-ray mission but with some cosmic-ray relevant results, see also here). Observations ended July 14, 2000.

• BeppoSAX [Satellite per Astronomia X] (operational May 1996 - April 2002)

• Chandra X-ray satellite

• CGRO [Compton Gamma Ray Observatory] (mission terminated) with the four experiments:

  • BATSE [Burst And Transient Source Experiment]

  • OSSE [Oriented Scintillation Spectrometer Experiment]

  • Comptel [imaging Compton telescope] (also here)

  • EGRET [Energetic Gamma Ray Experiment Telescope]

• Geotail (measures the Earth's magnetotail)

• GLAST [Gamma ray Large Area Space Telescope] (to be launched in Oct. 2007, see also NASA page)

• GRANAT gamma-ray satellite with several experiments (SIGMA, WATCH and others) was turned off November 27, 1998

  • SIGMA [Système d'Imagerie Gamma à Masque Aléatoire]

• HETE [High-Energy Transient Experiment] (launch failed on 4 Nov. 1996) has a follow-up:
  HETE-2 (launched October 9, 2000).

• IMP-8 (Interplanetary Monitoring Platform)

• INTEGRAL [INTErnational Gamma-Ray Astrophysics Laboratory] (launched October 17, 2002)

• NINA [New Instrument for Nuclear Analysis], a mission for low energy cosmic rays.

• PAMELA (magnet spectrometer, launched June 15, 2006). See also here.

• Polar (examines the Earth's magnetosphere and ionosphere)

• Rosat X-ray satellite (ended February 12, 1999)

• RXTE [Rossi X-ray Timing Explorer]

• SAMPEX [Solar Anomalous Magnetospheric Particle Explorer]

• Spectrum-X-Gamma satellite is a future mission (see also here and here)

• Suzaku X-ray satellite (Astro-E2 mission, see also this NASA page)

• SWIFT (gamma ray burst mission, launched November 20, 2004)

• Ulysses (explores interplanetary space at high solar latitudes)

• Voyager (two spacecrafts heading towards interstellar space)

• WIND (explores solar wind and plasma processes near the earth as well as gamma-ray bursts)

• XMM-Newton [X-ray Multi-mirror Mission] (see also pages at GSFC)

Some missions/experiments proposed or under development:

• ACCESS [Advanced Cosmic ray Composition Experiment for the Space Station] (see also pages at U. of Maryland)

• AGILE [Astro-rivelatore Gamma a Immagini LEggero] (a light-weight gamma-ray imager, see also here)

• Andromeda (a coded-aperture gamma-ray telescope)

• BLAST [Burst Locations with an Arc Second Telescope]

• EUSO [Extreme Universe Space Observatory ] (see also under fluorescence experiments)

• MEGA [Medium Energy Gamma-ray Astronomy]

• OWL [Orbiting Wide-angle Light-collectors] (see also under fluorescence experiments)

For a comprehensive list of high-energy astrophysics missions see here. For a list of gamma-ray missions see also this page.