Vernier thruster

<h2 id="examples">Examples</h2>

<ul><li>The <a href="/facts/R-7_family/G4HrfbkB">R-7 rocket family</a>, with over 1700 successful launches to date, still depends on the S1.358000 vernier thrusters in its first and second stage. Most of the larger Soviet missiles and launch vehicles also used verniers. Examples include the <a href="/facts/RD-8/lDXdNSyP">RD-8</a> on the <a href="/facts/Zenit_(rocket_family)/fkovnBhD">Zenit rocket family</a>, the <a href="/facts/RD-855/J0Kdh8FW">RD-855</a> and <a href="/facts/RD-856/9BBubNCT">RD-856</a> on the <a href="/facts/R-36_(missile)/ga1aBeDt">R-36</a>, and the <a href="/facts/RD-0214/VHhUA8dT">RD-0214</a> on the <a href="/facts/Proton_(rocket_family)/susmVN0U">Proton rocket family</a>.</li>
<li>On the <a href="/facts/Atlas_(rocket_family)/G4rKFbb7">SM-65 Atlas</a>, the <a href="/facts/Rocketdyne_LR-101/N5JwVwvA">LR-101 verniers</a> were used for roll control and to fine-tune the vehicle attitude after the main engine cutoff. The <a href="/facts/Delta_II/GoBa3Qch">Delta II</a> and <a href="/facts/Delta_III/KvtMal7W">Delta III</a> rocket also used the LR-101 for vehicle roll maneuver since one engine cannot do a roll maneuver (although the later <a href="/facts/GEM_46/wXHHlgdn">GEM 46</a> had thrust vectoring nozzle, only three were equipped with this feature and only ignited a brief moment during the ascent).<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a></li>
<li>The <a href="/facts/Space_Shuttle/7BoyetEv">Space Shuttle</a> had six vernier engines or thrusters in its "Vernier <a href="/facts/Reaction_Control_System/YfqBrd7h">Reaction Control System</a>" (<i>VRCS</i>).  The VRCS could also deliver a gentle steady thrust.  This was regularly used to boost the <a href="/facts/International_Space_Station/VNPUBz9m">International Space Station</a> while docked: for example during <a href="/facts/STS-130/Hjhp00Gb">STS-130</a> commander <a href="/facts/George_D._Zamka/txYfq2YK">George Zamka</a> and pilot <a href="/facts/Terry_W._Virts/d6o6z581">Terry Virts</a> fired <i><a href="/facts/Space_Shuttle_Endeavour/fcX8nN5Q">Endeavour</a>'</i>s VRCS for a duration of 33 minutes to attain an orbit between 180.5 and 190.0 <a href="/facts/Nautical_mile/V4yJzvKw">nmi</a> (334.3 and 351.9 km).<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a></li></ul>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Space_propulsion/KmpMGU9u">Space propulsion</a></li>
<li><a href="/facts/Cold_gas_thruster/XkUjyILE">Cold gas thruster</a></li>
<li><a href="/facts/Vernier_throttle/VfSvDsQ9">Vernier throttle</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Rocket Control: Examples of Controls". NASA's Glenn Research Center. Archived from the original on March 7, 2011. Retrieved December 30, 2011. <a href="https://web.archive.org/web/20110307070030/http://microgravity.grc.nasa.gov/education/rocket/rktcontrl.html" target="_blank">https://web.archive.org/web/20110307070030/http://microgravity.grc.nasa.gov/education/rocket/rktcontrl.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"Reaction Control Systems". NASA Kennedy Spaceflight Center. Retrieved 2011-10-03. The flight crew can select primary or vernier RCS thrusters for attitude control in orbit. Normally, the vernier thrusters are selected for on-orbit attitude hold. ... The forward RCS had 14 primaries and two vernier engines. The aft RCS had 12 primary and two vernier engines in each pod. The primary RCS engines provided 870 pounds of vacuum thrust each, and the verniers provided 24 pounds of vacuum thrust each. The oxidizer-to-fuel ratio for each engine is 1.6-to-1. The nominal chamber pressure of the primary thrusters was 152 psia. For each vernier, it was 110 psi. <a href="https://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-rcs.html" target="_blank">https://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-rcs.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>"Rocket Control: Examples of Controls". NASA's Glenn Research Center. Archived from the original on March 7, 2011. Retrieved December 30, 2011. <a href="https://web.archive.org/web/20110307070030/http://microgravity.grc.nasa.gov/education/rocket/rktcontrl.html" target="_blank">https://web.archive.org/web/20110307070030/http://microgravity.grc.nasa.gov/education/rocket/rktcontrl.html</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>"LR-101 VERNIER ENGINE". heroicrelics.org. Retrieved 24 June 2017. <a href="http://heroicrelics.org/info/lr-101/lr-101.html" target="_blank">http://heroicrelics.org/info/lr-101/lr-101.html</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>"Reaction Control Systems". NASA Kennedy Spaceflight Center. Retrieved 2011-10-03. The flight crew can select primary or vernier RCS thrusters for attitude control in orbit. Normally, the vernier thrusters are selected for on-orbit attitude hold. ... The forward RCS had 14 primaries and two vernier engines. The aft RCS had 12 primary and two vernier engines in each pod. The primary RCS engines provided 870 pounds of vacuum thrust each, and the verniers provided 24 pounds of vacuum thrust each. The oxidizer-to-fuel ratio for each engine is 1.6-to-1. The nominal chamber pressure of the primary thrusters was 152 psia. For each vernier, it was 110 psi. <a href="https://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-rcs.html" target="_blank">https://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-rcs.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Bergin, Chris (19 February 2010). "STS-130 prepares for undocking – MMOD impact on hatch cleared". NASAspaceflight.com. Retrieved 20 February 2010. <a href="http://www.nasaspaceflight.com/2010/02/sts-130-prep-undocking-mmod-impact-hatch-cleared/" target="_blank">http://www.nasaspaceflight.com/2010/02/sts-130-prep-undocking-mmod-impact-hatch-cleared/</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
</ol>

Vernier thruster open-in-new

Vernier thruster