"The travelers went to the space station."
Translation:tengchaH lujaH lengwI'pu'.
As David has pointed out, the -Daq is not incorrect, but perhaps not standard. We had not added it to the accepted translations, so I have now added it in.
Also, as pointed out by David, in this course we require some correspondence of the Klingon aspect markers to English complex tenses. Thus, in this course, lujaHlI' would be matched to "They were going to it."
When a verb includes a locative notion in itself, the way jaH does (its object is a location), using -Daq on the object is considered redundant, but not wrong. If you did it a lot Klingons would probably find it annoying. Hence tengchaH lujaH instead of tengchaHDaq lujaH.
The English sentence The travelers went to the space station sounds to my ear like it's describing a completed action: the trip is over; the travelers have arrived. The correct Klingon translation of this should be tengchaH lujaHpu' lengwI'pu' or tengchaH lujaHta' lengwI'pu' depending on whether you want to express the notion that the going was an action undertaken purposely. However, this course incorrectly assumes that Klingon perfective (-pu', -ta') equals English perfect tenses (have done, will have done, had done), and usually requires one to translate the other and vice versa. This is not correct Klingon.
Why not lujaHlI'? Because the action is not ongoing: -lI' means that the action is ongoing and has a known stopping point. That's not what's being described in this sentence.