7月13日，就在“发现”号即将起飞的两个小时前，美国航空航天局突然宣布推迟发射计划。因为工程人员监测到航天飞机燃料传感器出现问题，由于传感器是燃料箱和宇航员之间沟通的桥梁，通过它宇航员才能得知何时可以关掉引擎，以及航天飞机是否能正常运作。外电报道如下：NASA scrapped Wednesday's launch of the first shuttle flight in 2 1/2 years because of a fuel gauge that mistakenly read full instead of empty, a frustrating setback to the agency's bid to get back into space after the Columbia tragedy.

"All I can say is shucks," deputy shuttle program manager Wayne Hale said at a news conference of grim-faced NASA managers.

The launch was delayed until at least Saturday, and the postponement could last much longer, depending on the repairs needed.

Shucks在此意为“表达歉意”。Shucks是美国俚语，除了表示不满或歉意时所发的声音外，还有“呸！无聊！可恶！哪有这回事!”等含义，用来表示轻微的失望、厌恶或烦恼之意。和shucks有关的美俚还有no great shucks（没什么了不起）；not to care shucks（一点不在乎）等。

据悉，造成传感器失灵的原因有可能是零件生锈，由于传感器位于燃料箱的内部，因此更换传感器的工作相当费时。