If you are keen on keeping with the crowdfunding approach (you could probably combine it with bigchungus’ suggestions), I have a few tips that might help.
The first thing you need to do is get the pitch right – you need to make people care enough to give to the campaign. There are lots of charities and fundraisers out there asking for people’s cash, it’s a competitive space. I’d imagine a good angle would be that you and your group are plucky outsiders, and that this will help raise your aspirations, make a difference to the future of everyone in the group etc.
Congrats on reaching 20k people, that’s good work. It might be that the people you’ve reached so far might not be in a position to donate – if it’s mostly students, I can understand that. If I were you, I’d try to reach local minor celebs, local politicians, and encourage them to share your campaign. You can make this easier by drafting social media messages and email copy that they can use.
Depending on how big your local town is, the local media might also be interested in highlighting your efforts. If your college has a media team/press office, I’d approach them to ask if they can help pitch your fundraiser to local media. If your college doesn’t have a media team, I’d ask students that might be studying journalism or PR to help draft something that you could send in as a press release. If your college doesn’t do journalism/PR, I’d reach out to local media with your best pitch – “Local students aiming for the stars in NASA competition”-type stuff.
One last thought – your college might have some sort of alumni network. There might be a staff member or maybe even a team that manage the network. It might be worth approaching them to see if there are any alumni funds or options for sharing your campaign with the network.
Best of luck whatever way you go.