首页
登录
职称英语
As in the field of space travel, so in undersea exploration new technologies
As in the field of space travel, so in undersea exploration new technologies
游客
2024-07-30
48
管理
问题
As in the field of space travel, so in undersea exploration new technologies continue to appear. They share a number of similarities with each other—as well as some important differences.
Manned submersibles, like spaceships, must maintain living conditions in an unnatural environment. But while a spaceship must simply be sealed against the vacuum space, a submersible must be able to bear extreme pressure if it is not to break up in deep water.
In exploring space, unmanned vehicles were employed before astronauts. In undersea exploration, on the other hand, men paved the way, and only recently have unmanned remote-operated vehicles been put to use.
One reason for this is that communicating with vehicles in orbit is much easier than talking to those underwater. A vacuum is an ideal medium for radio communications, but underwater communications are limited to much slower sound waves. Thus, most undersea vehicle—particularly remote-operated vehicles—operated at the end of long ropes.
For a similar reason, knowing where you are undersea is much more difficult than in space. A spaceship’s position can be located by following its radio signal, or by using telescopes and radar. For an undersea vehicle, however, a special network of sonar devices must be laid out in advance on the ocean floor in the area of a dive to locate the vehicle’s position.
Though undersea exploration is more challenging than outer space in a number of respects, it has a distinct advantage: Going to the ocean depths doesn’t make it necessary to escape the Earth’s gravity. Thus, it remains far less expensive.
选项
答案
communication problem
解析
转载请注明原文地址:http://tihaiku.com/zcyy/3697910.html
相关试题推荐
Whydidn’tpeoplebegintouseunmannedvehiclesinunderseaexplorationuntilr
Whydidn’tpeoplebegintouseunmannedvehiclesinunderseaexplorationuntilr
Whydidn’tpeoplebegintouseunmannedvehiclesinunderseaexplorationuntilr
Formanyyears,Hawaiihasbeenamagicnametopeoplewholiketotravel.P
Formanyyears,Hawaiihasbeenamagicnametopeoplewholiketotravel.P
Formanyyears,Hawaiihasbeenamagicnametopeoplewholiketotravel.P
Formanyyears,Hawaiihasbeenamagicnametopeoplewholiketotravel.Pe
Thousandsofyearsago,travelingwasveryhard.Therewerenoroadsandnoc
Asageneralrule,it’sdangeroustotravelina(law)______country.lawless根据题
TRAVELTIPSNoSmokingFeder
随机试题
Theconceptofpersonalchoiceinrelationtohealthbehaviorsisanimporta
[originaltext]"WhereistheUniversity?"isthequestionmanyvisitorstoC
Itseemsindividualcancercellssendoutthesamedistresssignalsaswounds
[originaltext]W:Dad,canIgotoamoviewithSharon?M:Yeah,sure,butwait
[originaltext]Thekeyquestionforanyonlychildisthis:Whywereyouan
关于内幕信息,以下表述错误的是()A.非内部人传递的对市场价格产生影响的信息不会
根据材料,除印度外,我国对主要国家和地区货物进出口总额增长率最高的国家(地区)的
下列关于资本监管说法正确的是( )。A.经济资本是商业银行用于弥补预期损失的资
根据票据法律制度的规定,下列各项中,属于商业汇票独有的行为的是( )。A.出票
下列分部分项工程中,其专项施工方案必须进行专家论证的有( )。A.架体高度23
最新回复
(
0
)